Dual-Port Semiconductor Memory and First-In First-Out (FIFO) Memory Having Electrically Floating Body Transistor

ABSTRACT

Multi-port semiconductor memory cells including a common floating body region configured to be charged to a level indicative of a memory state of the memory cell. The multi-port semiconductor memory cells include a plurality of gates and conductive regions interfacing with said floating body region. Arrays of memory cells and method of operating said memory arrays are disclosed for making a memory device.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims priority to U.S. Provisional PatentApplication No. 61/413,992 which was filed on Nov. 16, 2010, and thecomplete disclosure of which is hereby incorporated by reference.

FIELD OF THE DISCLOSURE

The present disclosure is directed generally to semiconductor memorycells, and more particularly to multi-port semiconductor memory cellsthat include and/or utilize a common floating body region.

BACKGROUND OF THE DISCLOSURE

Semiconductor memory devices are used extensively to store data. Staticand Dynamic Random Access Memory (SRAM and DRAM, respectively) arewidely used in many applications. The semiconductor memory devicesinclude a plurality of memory cells, which also may be referred toherein as cells, each of which may exist in a plurality of memorystates, which also may be referred to herein as states, illustrative,non-exclusive examples of which include a logic-0 state and a logic-1state.

Conventional DRAM cells consist of a one-transistor and one-capacitor(1T/1C) structure. As the 1T/1C memory cell is scaled to smaller featuresizes, difficulties arise due to the need to maintain the capacitance ofthe capacitor.

DRAM based on the electrically floating body effect has been proposed(see, for example, “A Capacitor-less 1T-DRAM Cell”, S. Okhonin et al.,pp. 85-87, IEEE Electron Device Letters, vol. 23, no. 2, February 2002and “Memory Design Using One-Transistor Gain Cell on SOI”, T. Ohsawa etal., pp. 152-153, Tech. Digest, 2002 IEEE International Solid-StateCircuits Conference, February 2002). Such memory eliminates thecapacitor used in conventional 1T/1C memory cells, and thus is easier toscale to smaller feature sizes. In addition, such memory provides for asmaller cell size compared to the conventional 1T/1C memory cell.

However, unlike SRAM, such DRAM memory cells still require a refreshoperation, since the stored charge leaks over time.

A conventional DRAM refresh operation involves reading the state of thememory cell, followed by re-writing the memory cell with the same data.This read-then-write refresh requires two operations: a read operationand a write operation. The memory state of the memory cell cannot beaccessed while being refreshed. An “automatic refresh” method, whichdoes not require first reading the memory cell state, has been describedin Fazan et al., U.S. Pat. No. 7,170,807 and in “Autonomous Refresh ofFloating Body Cell (FBC), T. Ohsawa et al., pp. 801-804, Tech. Digest,2008 IEEE International Electron Devices Meeting. However, the automaticrefresh operation still interrupts access to the memory cells beingrefreshed.

In addition, a maximum charge that may be stored in a floating body DRAMmemory cell decreases with repeated read operations, leading to adecrease in a voltage difference among the plurality of memory statesavailable to the DRAM memory cell and degraded cell performance. Thisreduction in floating body charge may be due to charge pumping, wherethe floating body charge is attracted to the surface and trapped at theinterface (see for example “Principles of Transient Charge Pumping onPartially Depleted SOI MOSFETs”, S. Okhonin, et al., pp. 279-281, IEEEElectron Device Letters, vol. 23, no. 5, May 2002).

SRAM memory cells typically consist of six transistors (6T) and hencehave a large cell size when compared to DRAM. However, unlike DRAM, SRAMdoes not require periodic refresh operations to maintain its memorystate. Aside from the large cell size, 6T-SRAM also suffers from randomthreshold voltage (Vt) mismatches among its transistors, and requires avery complex custom manufacturing process for deep submicron ICfabrication.

Some electronic applications require the use of dual-port memory, whichis a memory device that has two independent ports; each of which mayperform the read and/or the write function. Existing dual-port memoriesuse SRAM technology, such as in the 8T and 10T dual-port SRAM describedby Chang, et al., US Patent Application Publication No. US 2007/0242513,and suffer from the same large cell size and random Vt mismatch problemsas in single-port SRAM. Existing dual-port SRAM cell size is more thantwice that of single-port SRAM cell size, and the dual-port SRAM cellalso has a more complex overhead circuitry.

Another specialized memory type that is very commonly used is first-infirst-out (FIFO) memory. FIFOs usually utilize dual-port SRAM and sufferfrom the same issues that SRAM memory cells suffer from, as mentionedabove.

Dual-port memory utilizing the floating body effect has been proposed,for example, in U.S. Pat. No. 7,085,156 “Semiconductor Memory Device andMethod of Operating Same”, R. Ferrant et al., and in U.S. Pat. No.7,285,832 “Multiport Single Transistor Bit Cell”, Hoefler et al. Thememory cell is formed by sharing the floating body regions of multiplefloating body DRAM cells and still requires the refresh operation, whichinterrupts access to the memory cell.

Thus there is a need for improved semiconductor memory devices andmethods of operating such devices such that the states of the memorycells of the semiconductor memory device are maintained withoutinterrupting memory cell access. There is also a need for improvedsemiconductor memory devices and methods of operating the same such thatthe states of the memory cells are not degraded with repeated readoperations.

In addition, there is also a need for improved semiconductor memorydevices and methods that decrease and/or avoid the use of difficult SRAMcustom doping to overcome random Vt mismatches in deep submicron processtechnology.

Furthermore, there is also a need for improved dual-port and FIFOmemories that satisfy the properties above and also have a smaller cellsize when compared to the traditional 6T SRAM cell.

SUMMARY OF THE DISCLOSURE

Multi-port semiconductor memory cells including a common floating bodyregion configured to be charged to a level indicative of a memory stateof the memory cell. The multi-port semiconductor memory cells include aplurality of gates and conductive regions interfacing with said floatingbody region. Arrays of memory cells and method of operating said memoryarrays are disclosed for making a memory device.

In some embodiments, the multi-port semiconductor memory cells includedual-port semiconductor memory cells. In some embodiments, themulti-port semiconductor memory cells include more than two ports. Insome embodiments, the multi-port semiconductor memory cells are formedon a substrate that includes an insulating layer between the floatingbody region and the substrate. In some embodiments, the multi-portsemiconductor memory cells are formed on a substrate that includes aburied layer between the floating body region and the substrate. In someembodiments, the multi-port semiconductor memory cells includethree-dimensional fin-type memory cells.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 provides a schematic representation of an illustrative,non-exclusive example of a first embodiment of a memory cell accordingto the present disclosure.

FIG. 2 provides a schematic representation of an equivalent circuitdiagram of the memory cell of FIG. 1.

FIG. 3 provides a schematic representation of an illustrative,non-exclusive example of a row and/or column of memory cells accordingto the present disclosure.

FIG. 4 provides a schematic representation of an illustrative,non-exclusive example of an array of memory cells of the firstembodiment according to the present disclosure.

FIGS. 5-6 provide illustrative, non-exclusive examples of biasingconditions that may be utilized during various operations of the firstembodiment of a memory cell according to the present disclosure.

FIG. 7 provides a schematic representation of an illustrative,non-exclusive example of a read circuitry that may be utilized with thefirst embodiment of a memory cell according to the present disclosure.

FIGS. 8-9 provide three-dimensional schematic representations ofillustrative, non-exclusive examples of the first embodiment of a memorycell according to the present disclosure.

FIG. 10 provides a schematic representation of a top view of the memorycell of FIG. 8.

FIG. 11 provides a schematic representation of an illustrative,non-exclusive example of a quad-port memory cell of the first embodimentof a memory cell according to the present disclosure.

FIG. 12 provides a schematic representation of an illustrative,non-exclusive example of a second embodiment of a memory cell accordingto the present disclosure.

FIG. 13 provides a schematic representation of an illustrative,non-exclusive example of an array of memory cells of the secondembodiment according to the present disclosure.

FIG. 14 provides a schematic representation of a first equivalentcircuit diagram of the memory cell of FIG. 12.

FIG. 15 provides a schematic representation of a second equivalentcircuit diagram of the memory cell of FIG. 12.

FIGS. 16-19 provide illustrative, non-exclusive examples of biasingconditions that may be utilized during various operations of the secondembodiment of a memory cell according to the present disclosure.

FIGS. 20-21 provide schematic representations of illustrative,non-exclusive examples of refresh circuitry that may be utilized tomaintain a memory state of the second embodiment of a memory cellaccording to the present disclosure.

FIG. 22 is a plot of a maximum floating body potential as a function ofthe potential that may be applied to a substrate terminal for the secondembodiment of a memory cell according to the present disclosure.

FIG. 23 is a plot of a floating body region net current for differentfloating body region potentials as a function of the voltage that may beapplied to the substrate terminal for the second embodiment of a memorycell according to the present disclosure.

FIGS. 24-25 provide three-dimensional schematic representations ofillustrative, non-exclusive examples of the second embodiment of amemory cell according to the present disclosure.

FIG. 26 provides a schematic representation of a top view of the memorycell of FIG. 24.

FIG. 27 provides a schematic representation of an illustrative,non-exclusive example of a quad-port memory cell according to the secondembodiment of a memory cell according to the present disclosure.

FIG. 28 provides a schematic representation of an illustrative,non-exclusive example of a third embodiment of a memory cell accordingto the present disclosure.

FIG. 29 provides a schematic representation of an illustrative,non-exclusive example of an array of memory cells of the thirdembodiment according to the present disclosure.

FIG. 30 provides a schematic representation of a first equivalentcircuit diagram of the memory cell of FIG. 28.

FIG. 31 provides a schematic representation of a second equivalentcircuit diagram of the memory cell of FIG. 28.

FIGS. 32-33 provide three-dimensional schematic representations ofillustrative, non-exclusive examples of the third embodiment of a memorycell according to the present disclosure.

FIG. 34 provides a schematic representation of a top view of the memorycell of FIG. 32.

FIG. 35 provides a schematic representation of an illustrative,non-exclusive example of a quad-port memory cell of the third embodimentof a memory cell according to the present disclosure.

FIG. 36 provides a schematic representation of an illustrative,non-exclusive example of a fourth embodiment of a memory cell accordingto the present disclosure.

FIG. 37 provides a schematic representation of an illustrative,non-exclusive example of an array of memory cells of the fourthembodiment according to the present disclosure.

FIG. 38 provides a schematic representation of an illustrative,non-exclusive example of the two-dimensional layout of the array ofmemory cells of FIG. 37.

FIG. 39 provides a schematic representation of another illustrative,non-exclusive example of the two-dimensional layout of the array ofmemory cells of FIG. 37.

FIG. 40 provides a schematic representation of an illustrative,non-exclusive example of a cross section of the fourth embodiment of amemory cell taken along line II-II′ of FIG. 38.

FIGS. 41-42 provide three-dimensional schematic representations ofillustrative, non-exclusive examples of the fourth embodiment of amemory cell according to the present disclosure.

FIG. 43 provides a schematic representation of a top view of the memorycell of FIG. 41.

FIG. 44 provides a schematic representation of an illustrative,non-exclusive example of a transistor that may be utilized with a fifthembodiment of a memory cell according to the present disclosure.

FIG. 45 provides a schematic representation of an illustrative,non-exclusive example of the fifth embodiment of a memory cell accordingto the present disclosure.

FIG. 46 provides a simplified equivalent circuit diagram of the fifthembodiment of a memory cell according to the present disclosure.

FIG. 47 provides a schematic representation of an illustrative,non-exclusive example of an array of memory cells of the fifthembodiment according to the present disclosure.

FIG. 48 provides another schematic representation of an illustrative,non-exclusive example of an array of memory cells of the fifthembodiment according to the present disclosure.

FIG. 49 provides a schematic representation of an equivalent circuitdiagram of the memory cell of FIG. 46.

FIGS. 50-57 provide illustrative, non-exclusive examples of biasingconditions that may be utilized during various operations of the fifthembodiment of a memory cell according to the present disclosure.

FIG. 58 provides a schematic representation of an illustrative,non-exclusive example of refresh circuitry that may be utilized tomaintain a memory state of the fifth embodiment of a memory cellaccording to the present disclosure.

FIG. 59 provides a schematic representation of an illustrative,non-exclusive example of read circuitry that may be utilized with thefifth embodiment of a memory cell according to the present disclosure.

FIG. 60 provides an illustrative, non-exclusive example of biasingconditions that may be utilized during the row-wide write ‘1’ with gateassist operation on the array of FIG. 48.

FIGS. 61-62 provide three-dimensional schematic representations ofillustrative, non-exclusive examples of the fifth embodiment of a memorycell according to the present disclosure.

FIG. 63 provides a schematic representation of a top view of the memorycell of FIG. 57.

FIG. 64 provides a schematic representation of an illustrative,non-exclusive example of a transistor that may be utilized with a sixthembodiment of a memory cell according to the present disclosure.

FIG. 65 provides a schematic representation of an illustrative,non-exclusive example of the sixth embodiment of a memory cell accordingto the present disclosure.

FIG. 66 provides a simplified equivalent circuit diagram of the sixthembodiment of a memory cell according to the present disclosure.

FIG. 67 provides a schematic representation of an illustrative,non-exclusive example of an array of memory cells of the sixthembodiment according to the present disclosure.

FIG. 68 provides another schematic representation of an illustrative,non-exclusive example of an array of memory cells of the sixthembodiment according to the present disclosure.

FIG. 69 provides a schematic representation of an equivalent circuitdiagram of the memory cell of FIG. 61.

FIGS. 70-77 provide illustrative, non-exclusive examples of biasingconditions that may be utilized during various operations of the sixthembodiment of a memory cell according to the present disclosure.

FIG. 78 provides an illustrative, non-exclusive example of biasingconditions that may be utilized during the row-wide write ‘1’ with gateassist operation that may be utilized with the array of FIG. 64.

FIGS. 79-80 provide three-dimensional schematic representations ofillustrative, non-exclusive examples of the sixth embodiment of a memorycell according to the present disclosure.

FIG. 81 provides a schematic representation of a top view of the memorycell of FIG. 71.

FIG. 82 provides a schematic representation of an illustrative,non-exclusive example of a true dual-port memory that may include thememory cells according to the present disclosure.

FIG. 83 provides a schematic representation of another illustrative,non-exclusive example of a true dual-port memory that may include thememory cells according to the present disclosure.

FIG. 84 provides a schematic representation of an illustrative,non-exclusive example of a first-in-first-out memory circuitry that mayinclude the memory cells according to the present disclosure.

DETAILED DESCRIPTION AND BEST MODE OF THE DISCLOSURE

Before the present systems, devices and methods are described, it is tobe understood that the present disclosure is not limited to theparticular embodiments described, as such may, of course, vary. It isalso to be understood that the terminology used herein is for thepurpose of describing particular embodiments only, and is not intendedto be limiting, since the scope of the present common body will belimited only by the appended claims.

Where a range of values is provided, it is to be understood that eachintervening value, to the tenth of the unit of the lower limit unlessthe context clearly dictates otherwise, between the upper and lowerlimits of that range is also specifically disclosed. Each smaller rangebetween any stated value or intervening value in a stated range and anyother stated or intervening value in that stated range is encompassedwithin the present disclosure. The upper and lower limits of thesesmaller ranges may independently be included or excluded in the range,and each range where either, neither or both limits are included in thesmaller ranges is also encompassed within the present disclosure,subject to any specifically excluded limit in the stated range. Wherethe stated range includes one or both of the limits, ranges excludingeither or both of those included limits are also included in the presentdisclosure.

Unless defined otherwise, all technical and scientific terms used hereinhave the same meaning as commonly understood by one of ordinary skill inthe art to which this disclosure belongs. Although any methods and/ormaterials similar and/or equivalent to those described herein may beused in the practice and/or testing of the systems and methods accordingto the present disclosure, illustrative, non-exclusive examples ofmethods and materials are now described. All publications mentionedherein are incorporated herein by reference in their entirety.

As used herein and in the appended claims, the singular forms “a”, “an”,and “the” include plural referents unless the context clearly dictatesotherwise. Thus, for example, reference to “a cell” includes a pluralityof such cells and reference to the “terminal” includes reference to oneor more terminals and equivalents thereof known to those skilled in theart, and so forth.

The publications discussed herein are provided solely for theirdisclosure prior to the filing date of the present application. Nothingherein is to be construed as an admission that the present disclosure isnot entitled to antedate such publication by virtue of prior invention.Further, the dates of publication provided may be different from theactual publication dates, which may need to be independently confirmed.

In the following discussion and the related Figures, like numbers mayrefer to like and/or similar structures. After being introduced and/ordiscussed with reference to one Figure, a given structure and/or numbermay not be discussed in detail herein in subsequent structures and/orFigures that include the same number and/or structure.

DEFINITIONS

A “holding operation”, “standby operation” or “holding/standbyoperation”, as used herein, refer to a process of sustaining a state ofa memory cell by maintaining the stored charge. Maintenance of thestored charge may be facilitated by applying a back bias to the cell ina manner described herein.

A “back bias terminal” refers to a terminal at the back side of asemiconductor transistor device, usually at the opposite side of thegate of the transistor. A back bias terminal is also commonly referredto as a “back gate terminal”. Herein, the back bias terminal may referto the substrate terminal and/or the buried well terminal, dependingupon the embodiment being described.

The term “back bias” refers to a voltage applied to a back biasterminal.

DETAILED DESCRIPTION

FIG. 1 is a schematic representation of an illustrative, non-exclusiveexample of a first embodiment 1 of a memory cell 9, which also may bereferred to herein as a cell 9, according to the present disclosure. Theembodiment of FIG. 1 also may be referred to herein as a dual-portmemory cell 1, a memory cell 1, and/or a cell 1. Cell 1 is formed inand/or on a substrate 12 of a first conductivity type, such as a p-typeconductivity type, for example. Substrate 12 may include any suitablesubstrate, an illustrative, non-exclusive example of which includes asilicon on insulator (SOI) substrate. Similarly, substrate 12 may beformed from any suitable semiconductor material, illustrative,non-exclusive examples of which include silicon, germanium, silicongermanium, gallium arsenide, carbon nanotubes, and/or othersemiconductor materials.

Substrate 12 has a surface 14 and includes a buried insulator layer 22.Buried insulator layer 22 may include any suitable dielectric material,an illustrative, non-exclusive example of which includes silicon oxide.

Memory cell 1 includes a first region 18 having a second conductivitytype, such as an n-type conductivity type, that is formed in substrate12, a second region 16 having the second conductivity type that isformed in substrate 12 and spaced apart from the first region 18, and athird region 20 having the second conductivity type that is formed insubstrate 12 and spaced apart from the first and second regions 18 and16, respectively. First, second and third regions 18, 16 and 20,respectively, may be exposed at and/or proximal to surface 14 and may beformed using any suitable method and/or process, illustrative,non-exclusive examples of which include ion implantation and/or solidstate diffusion.

A floating body region 24, which also may be referred to herein as acommon body region 24 and/or a shared body region 24, having a firstconductivity type, such as a p-type conductivity type, is bounded bysurface 14, first, second and third regions 18, 16, and 20,respectively, and by buried insulator layer 22. Floating body region 24may be formed using any suitable method and/or process, illustrative,non-exclusive examples of which include an ion implantation processand/or epitaxial growth. Multiple cells 1 may be joined in an array 81to form a memory device and/or a portion thereof 10 as illustrated inFIGS. 3 and 4.

Referring back to FIG. 1, the method and/or process utilized to formfirst and third regions 18 and 20, respectively, may be optimized suchthat the regions 18 and 20 reach buried insulator layer 22 and insulatefloating body 24 from a neighboring floating body 24 of an adjacent cellwhen multiple cells 1 are joined in an array 81. On the other hand, themethod and/or process utilized to form second region 16 may be optimizedsuch that region 16 does not reach buried insulator layer 22. Therefore,floating body 24 is not isolated on the side by the first region 16.

A first gate 60 may be positioned in between the regions 16 and 18, andabove the surface 14. A second gate 64 may be positioned in between theregions 16 and 20, and above the surface 14. Gate 60 is insulated fromsurface 14 by a first insulating layer 62 and gate 64 is insulated fromsurface 14 by a second insulating layer 66. Insulating layers 62 and 66may be formed from any suitable dielectric material, illustrative,non-exclusive examples of which include silicon oxide, high-K dielectricmaterials, tantalum peroxide, titanium oxide, zirconium oxide, hafniumoxide, and/or aluminum oxide. Gates 60 and 64 may be made from anysuitable conductive material, illustrative, non-exclusive examples ofwhich include a polysilicon material, a metal gate electrode, tungsten,tantalum, titanium and/or their nitrides.

Cell 1 further includes a word line #1 (WL1) terminal 70 electricallyconnected to gate 60, a word line #2 (WL2) terminal 76 electricallyconnected to gate 64, a source line (SL) terminal 72 electricallyconnected region 16, a bit line #1 (BL1) terminal 74 electricallyconnected to region 18, a bit line #2 (BL2) terminal 77 electricallyconnected to region 20, and a substrate terminal 78 electricallyconnected to substrate 12. WL1 terminal 70 and BL1 terminal 74 also maybe referred to herein as ‘port #1’. Similarly, WL2 terminal 76 and BL2terminal 77 also may be referred to herein as ‘port #2’.

As discussed in more detail herein, the conductivity types describedabove are exemplary conductivity types and other conductivity typesand/or relative conductivity types are also within the scope of thepresent disclosure. As an illustrative, non-exclusive example, memorycell 1 may have and/or include an n-type conductivity type as the firstconductivity type and a p-type conductivity type as the secondconductivity type.

As shown in the illustrative, non-exclusive example of FIG. 1, memorycells 9 according to the present disclosure may be configured and/orconstructed such that a single cross-section of the memory cell (i.e., asingle plane) that is taken in a direction that is at leastsubstantially perpendicular to a plane of substrate 12 may pass throughthe floating body region, each of the plurality of conductive regions,and each of the plurality of gates that are associated with the memorycell. Similarly, the single cross-section (i.e., the single plane) maypass through each of the plurality of ports that is included in thememory cell. Thus, each of floating body region 24, conductive regions16, 18, and 20, and gates 60 and 64 are included in the singlecross-section of FIG. 1.

Such memory cells may be referred to herein as elongate memory cells 9,planar memory cells 9, series memory cells 9, and/or linear memory cells9. These memory cells also may be referred to herein as elongate,planar, series, and/or linear semiconductor memory cells 9, multi-portsemiconductor memory cells 9, and/or multi-port memory cells 9. Suchmemory cells further may be referred to as including a plurality ofcross-sectionally coplanar ports, a plurality of cross-sectionallycoplanar conductive regions, and/or a plurality of cross-sectionallycoplanar gates. Adjacent rows of such memory cells 9 may be separated byan insulating region, for example, insulating region 28 as shown in theschematic illustration of a top-view of the memory cells 9 shown inFIGS. 10, 38, and 39.

FIG. 2 is an illustrative, non-exclusive example of an equivalentcircuit diagram for memory cell 1 of FIG. 1. As shown in FIG. 2, memorycell 1 includes first n-type metal oxide semiconductor field-effecttransistor (MOSFET) 130, which is formed by gate 60, BL1 region 18, SLregion 16, and floating body 24, and second MOSFET 131, which is formedby gate 64, BL2 region 20, SL region 16, and floating body 24. Memorycell 1 also includes first n-p-n bipolar device 132, which is formed byfloating body 24, BL1 region 18, and SL region 16, and second n-p-nbipolar device 133, which is formed by floating body 24, BL2 region 20,and SL region 16. P-type substrate 12 of the current embodiment of thememory cell 1 will be grounded. It can be seen that dual-port memorycell 1 consists of two field-effect transistors 130 and 131 connected inseries, where SL region 16 and floating body 24 is shared between thetwo field-effect transistors.

As shown in FIGS. 3 and 4, and discussed in more detail herein, aplurality of memory cells 1 may be combined in a column 79, a row 80,and/or an array 81 of columns 79 and rows 80, which also may be referredto herein as a memory array 81, to form a memory device 10. FIG. 3provides an illustrative, non-exclusive example of 3 adjacent cells 1′,1″, and 1′″ on row ‘a’ connected together with shared bit lines, whereevery other row of array 81 is mirrored from its previous row. FIG. 4provides an illustrative, non-exclusive example of array 81 made up ofcells 1. In FIG. 4, each cell is denoted by ‘1 xy’ cell locationnotation, where the number ‘1’ refers to cell 1, the ‘x’ refers to therow and the ‘y’ refers to the column locations.

Each row 80 in array 81 may include a plurality of memory cells 1.Because first region 18 and third region 20, which also may be referredto herein as active regions 18 and 20, respectively, are open-ended atthe boundary of cell 1, without any insulator and/or othernon-conductive structure therebetween, they may combine with the regions18 and 20 of the adjacent cells when multiple cells 1 are joinedtogether to form column 79 and/or memory array 81. In order to preventshorting of port #1 and port #2 bit lines, the adjacent memory portterminals may be mirrored to each other.

As an illustrative, non-exclusive example, and as shown in FIG. 3,region 18 and BL1 terminal 74 a of cell 1″ are shared with adjacent cell1′″ immediately next to region 18. Similarly, region 20 and BL2 terminal77 a of cell 1′ are shared together with the adjacent cell 1″immediately next to region 20.

Memory cells 1 may be operated with a plurality of different biasingconditions, and the response of memory cells 1 to the different biasingconditions may vary with the particular conditions, as well as thememory state of the memory cells. This may include operating the memorycells in a plurality of modes, or operational modes, illustrative,non-exclusive examples of which include an idle mode, in which memorycell 1 may not be actively retaining a memory state, and a holding mode,in which memory cell 1 may be actively retaining the memory state.Additionally or alternatively, this also may include operating and/orutilizing the memory cell in a plurality of operations, illustrative,non-exclusive examples of which include read operations, in which thememory state of the memory cell is being accessed, or read, by anothercircuit and/or device, such as a read circuit, and write operations, inwhich the memory state of the memory cell is set to a desired, target,or specific memory state by another circuit and/or device, such as awrite circuit.

FIGS. 5 and 6 provide illustrative, non-exclusive examples of biasingconditions that may be applied to memory cells 1 and/or that may beassociated with and/or included in at least a portion of the pluralityof modes in which the memory cells may be operated and/or operations inwhich the memory cells may be utilized. Illustrative, non-exclusiveexamples of the response of memory cell 1 to these various biasingconditions, as well as the modes and/or the operations thereof, arediscussed in more detail herein.

As discussed in more detail herein, memory cell 1, column 79, row 80,and/or array 81 of memory device 10 may be operated in an idle mode, inwhich the memory cell may not be actively retaining the memory state.With reference to FIG. 1, memory cell 1 may be in the idle mode underthe following conditions: zero voltage is applied to terminals 78, 72,74 and 77, and a zero or negative voltage is applied to terminals 70 and76. In one particular non-limiting embodiment, approximately 0.0 voltmay be applied to terminals 78, 72, 74, 77, 70 and 76. However, thesevoltage levels may vary.

When memory cell 1 is in the idle mode and floating body 24 includes apositive charge, the positive charge stored in floating body region 24will decrease over time due to the p-n diode leakage from floating body24 to regions 16, 18, 20 and due to charge recombination. Thus, aperiodic holding operation may be utilized to maintain the positivecharge stored in the floating body 24. Illustrative, non-exclusiveexamples of periodic holding operations according to the presentdisclosure include 1) a row-wide holding operation, 2) a column-wideholding operation by port #1, 3) a column-wide holding operation by port#2, and 4) a column-wide holding operation simultaneously by ports #1 &#2.

Referring now to FIG. 1 for a single memory cell 1 and FIG. 4 for anarray 81 of memory cells 1, illustrative, non-exclusive examples of thebiasing conditions for the row-wide holding operation, as shown in FIG.5, are presented below. The biasing conditions for the terminals of thesingle memory cell of FIG. 1 are indicated first and are followed (inparenthesis) by the biasing conditions for a row-wide holding operationon row “a” of array 81 of FIG. 4. The row-wide holding operation on row“a” may be performed by applying a zero bias, or voltage, to substrateterminal 78, a zero voltage to BL1 terminal 74 (columns 74 a-74 n), azero or negative voltage to WL1 terminal 70 (rows 70 a-70 p), a positivevoltage to SL terminal 72 in the row upon which the holding operation isperformed (i.e. row 72 a), a zero voltage to the remaining SL terminalsof array 81 (rows 72 b-72 p), a zero or negative voltage to WL2 terminal76 (rows 76 a-76 p), and a zero voltage to BL2 terminal 77 (columns 77a-77 n).

If floating body region 24 is positively charged (i.e. in the logic-1state, which also may be referred to herein as state ‘1’ and/or state1), bipolar devices 132 and 133 (of FIG. 2) will be turned on. Afraction of the bipolar device current will flow into floating bodyregion 24 (which may be referred to herein as the base current) andmaintain the state ‘1’ data.

The efficiency of the holding operation may be enhanced by designingbipolar devices 132 and 133 to be low-gain bipolar devices, where thebipolar gain is defined as the ratio of the collector current flowingout of regions 16 to the base current flowing into floating body region24. If floating body region 24 is not positively charged (i.e. in thelogic-0 state, which also may be referred to herein as state ‘0’ and/orstate 0), bipolar devices 132 and 133 will not be turned on.Consequently, no base current will flow into floating body region 24.Therefore, memory cells in state ‘0’ will remain in state ‘0’.

In one particular non-limiting embodiment, and as shown in FIG. 5, therow-wide holding operation may include the application of approximately0.0 volts to terminals 78, 74, 70, 76 and 77, and approximately +1.2volts to terminal 72 of the memory device of FIG. 1. However, thesevoltage levels may vary.

Illustrative, non-exclusive examples of biasing conditions for thecolumn-wide holding operation by port #1 on column “a”, as shown in FIG.5, are discussed in more detail below. The column-wide holding operationby port #1 may be performed by applying a zero bias to the substrateterminal 78, a positive voltage to BL1 terminal 74 in the column uponwhich the holding operation is performed (i.e., column 74 a), a zerovoltage to the remaining BL1 terminals of array 81 (columns 74 b-74 n),a zero or negative voltage to WL1 terminal 70 (rows 70 a-70 p), a zerovoltage to SL terminal 72 (rows 72 a-72 p), a zero or negative voltageto WL2 terminal 76 (rows 76 a-76 p) and a zero voltage to BL2 terminal77 (columns 77 a-77 n).

If floating body 24 is positively charged (i.e. in state ‘1’), thebipolar device 132 formed by SL region 16, floating body 24, and region18 will be turned on. A fraction of the bipolar transistor current willthen flow into floating body region 24 and maintain the state ‘1’ data.

For memory cells in state ‘0’ data, the bipolar devices 132 and 133 willnot be turned on. Consequently, no base hole current will flow intofloating body region 24. Therefore, memory cells in state ‘0’ willremain in state ‘0’.

In one particular non-limiting embodiment, and as shown in FIG. 5, thecolumn-wide holding operation by port #1 may include the application ofapproximately 0.0 volts to terminals 78, 72, 70, 76 and 77, andapproximately +1.2 volts to terminal 74. However, these voltage levelsmay vary.

The biasing conditions for the column-wide holding operation by port #2on column “a”, as shown in FIG. 5, are substantially similar to thebiasing conditions for the column-wide holding operation by port #1 oncolumn “a”, with the exception that the positive voltage may be appliedto BL2 terminal 77 in the column upon which the holding operation isperformed (column 77 a) and a zero voltage may be applied to BL1terminal 74 in the column upon which the holding operation is performed(column 74 a).

If floating body 24 is positively charged (i.e. in a state ‘1’), thebipolar device 133 formed by SL region 16, floating body 24, and region20 will be turned on. A fraction of the bipolar transistor current willthen flow into floating body region 24 and maintain the state ‘1’ data.

For memory cells in state ‘0’ data, the bipolar devices 132 and 133 willnot be turned on. Consequently no base hole current will flow intofloating body region 24. Therefore, memory cells in state ‘0’ willremain in state ‘0’.

In one particular non-limiting embodiment, and as shown in FIG. 5, thecolumn-wide holding operation by port #2 may include the application ofapproximately 0.0 volts to terminals 78, 74, 70, 76 and 72, andapproximately +1.2 volts to terminal 77. However, these voltage levelsmay vary.

The biasing conditions for the column-wide holding operation on column“a” simultaneously by ports #1 and #2, as shown in FIG. 5, aresubstantially similar to the biasing conditions for the column-wideholding operation by port #1 on column “a”, with the exception that thepositive voltage may be applied to both BL1 terminal 74 and BL2 terminal77 in the column upon which the holding operation is performed (columns74 a and 77 a). A zero voltage may be applied to the remainder of theBL1 and BL2 terminals (terminals 74 b-74 p and 77 b-77 p). If floatingbody 24 is positively charged (i.e. in a state ‘1’), the bipolar devices132 and 133 formed by SL region 16, floating body 24, and regions 18 and20, respectively, will be turned on. A fraction of the bipolartransistor current will flow into floating body region 24 and maintainthe state ‘1’ data.

For memory cells in state ‘0’ data, the bipolar devices 132 and 133 willnot be turned on. Consequently no base hole current will flow intofloating body region 24. Therefore, memory cells in state ‘0’ willremain in state ‘0’.

In one particular non-limiting embodiment, and as shown in FIG. 5, thecolumn-wide holding operation on column “a” simultaneously by ports #1and #1 may include the application of approximately 0.0 volts toterminals 78, 72, 70 and 76, and approximately +1.2 volts to terminals74 and 77. However, these voltage levels may vary.

While the above holding operations have been discussed in the context ofa holding operation that is performed on column “a” or row “a”, it iswithin the scope of the present disclosure that the holding operation(s)may be performed on any suitable portion of a column 79, portion of arow 80, entire column 79, entire column 80, multiple columns 79, and/ormultiple rows 80, such as when a plurality of columns 79 and/or rows 80are electrically connected in series and/or parallel.

The charge stored in the floating body 24 may be sensed by monitoringthe cell current of memory cell 1. If cell 1 is in state ‘1’ havingholes in the floating body region 24, then the memory cell will have alower threshold voltage (gate voltage where the transistor is turnedon), and consequently a higher cell current, when compared to when cell1 is in a state ‘0’ having no holes in floating body region 24. Themonitoring may be accomplished in any suitable manner and using anysuitable circuit and/or circuits. FIG. 7 provides an illustrative,non-exclusive example of a read circuitry architecture that may beutilized with arrays 81 of memory cells 1 and/or 9 according to thepresent disclosure.

In FIG. 7, sensing circuit/read circuitry 90, which may be connected toBL1 terminal 74 and/or BL2 terminal 77 of memory array 81, may be usedto determine the data state of the memory cell. Examples of the readoperation is described in “A Design of a Capacitorless 1T-DRAM CellUsing Gate-Induced Drain Leakage (GIDL) Current for Low-power andHigh-speed Embedded Memory”, and Yoshida et al., pp. 913-918,International Electron Devices Meeting, 2003 and U.S. Pat. No. 7,301,803“Bipolar reading technique for a memory cell having an electricallyfloating body transistor”, both of which are hereby incorporated herein,in their entireties, by reference thereto. An example of a sensingcircuit is described in “An 18.5 ns 128 Mb SOI DRAM with a Floating bodyCell”, Ohsawa et al., pp. 458-459, 609, IEEE International Solid-StateCircuits Conference, 2005, which is hereby incorporated herein, in itsentirety, by reference thereto.

A read operation in dual port memory cell 1 may be performedindependently by port #1 and/or port #2 irrespective of timing. However,read and write operations may not occur simultaneously in order todecrease a potential for reading incorrect data. This process may bereferred as write contention avoidance and is discussed in more detailherein.

Referring to FIG. 1 for a single memory cell 1 and FIG. 4 for an array81 of memory cells, illustrative, non-exclusive examples of the biasingconditions for a read port #1 only operation, as shown in FIG. 5, arepresented below. The read port #1 only operation on cell 1 aa may beperformed by applying a zero voltage to substrate terminal 78, a zerovoltage to SL terminal 72 (rows 72 a-72 p), a positive voltage to theselected BL1 terminal 74 (column 74 a), a zero voltage to the remainingBL1 terminals of array 81 (columns 74 b-74 n), a positive voltagegreater than the positive voltage applied to the selected BL1 terminal74 (74 a) to the selected WL1 terminal 70 (row 70 a), a zero or negativevoltage to the remaining WL1 terminals of array 81 (rows 70 b-70 p), azero or negative voltage to WL2 terminal 76 (rows 76 a-76 p), and a zerovoltage to BL2 terminal 77 (columns 77 a-77 n).

Similarly, and as also shown in FIG. 5, the read port #2 only operationmay be performed on cell 1 aa. The read port #2 operation may beperformed by applying a zero voltage to substrate terminal 78, a zerovoltage to SL terminal 72 (rows 72 a-72 p), a zero voltage to BL1terminal 74 (columns 74 a-74 n), a zero or negative voltage to WL1terminal 70 (rows 70 a-70 p), a positive voltage to the selected BL2terminal 77 (column 77 a), a zero voltage to the remaining BL2 terminalsof array 81 (columns 77 b-77 n), a positive voltage greater than thepositive voltage applied to the selected BL2 terminal 77 (77 a) to theselected WL2 terminal 76 (row 76 a), and a zero or negative voltage tothe remaining WL2 terminals of array 81 (rows 76 b-76 p).

Additionally or alternatively, and as also shown in FIG. 5, simultaneousread operations by port #1 and port #2 also may be performed on cell 1aa. The simultaneous read operations may be performed by applying a zerovoltage to substrate terminal 78, a zero voltage to SL terminal 72 (rows72 a-72 p), a positive voltage to the selected BL1 terminal 74 (column74 a) and the selected BL2 terminal 77 (column 77 a), a zero voltage tothe remaining BL1 and BL2 terminals of array 81 (columns 74 b-74 n and77 b-77 n), a positive voltage greater than the positive voltage appliedto the selected BL1 terminal 74 (column 74 a) and the selected BL2terminal 77 (column 77 a) to the selected WL1 terminal 70 (row 70 a) andthe selected WL2 terminal 76 (row 76 a), and a zero or negative voltageto the remaining WL1 and WL2 terminals of array 81 (rows 70 b-70 p and76 b-76 p).

In one particular non-limiting embodiment, and as shown in FIG. 5, about0.0 volts is applied to terminal 72, about +0.4 volts is applied to theselected terminal 74 a and/or 77 a, about +1.2 volts is applied toselected terminal 70 a and/or 76 a, and about 0.0 volts is applied toterminal 78. The unselected terminals 74 or 77 remain at 0.0 volts andthe unselected terminal 70 or 76 remain at 0.0 volts. However, thesevoltage levels may vary while maintaining the relative relationshipsbetween voltage levels as generally described above.

As a result of the bias conditions applied as described, the unselectedmemory cells will be at idle mode, maintaining the states of therespective floating bodies 24 thereof. Furthermore, the idle mode doesnot interrupt the read operation of the selected memory cell 1 aa.Similarly, read operation on port #1 may be performed on any differentcell in array 81 from read operation on port #2 simultaneously. As anillustrative, non-exclusive example, this may include reading port #1 oncell 1 aa and reading port #2 on cell 1 bb simultaneously.

For memory cells 1 sharing the same row as the selected memory cell, BLterminals 74 or 77 and substrate terminal 78 are at about 0.0 volt. Ascan be seen, these cells will be at idle mode because the emitter andcollector terminals of intrinsic n-p-n bipolar devices 132 and 133 willbe at zero potential and no current will flow from cell 1. For memorycells 1 sharing the same column as the selected memory cell, a positivevoltage is applied to BL terminals 74 or 77. However, WL terminal 70 or76 is at zero volts and MOSFET transistor 130 or 131 is turned off.Thus, no current flows from regions 18 or 20 to region 16.

For memory cells 1 not sharing the same row or the same column as theselected memory cell, SL terminal 72, BL terminals 74 or 77 and WLterminals 70 or 76 are at about 0.0 volts. As can be seen, these cellswill be at idle mode. Thus, unselected memory cells 1 during a readoperation will remain in idle mode.

Writing ‘0’ to cell 1 may be accomplished by utilizing a plurality ofbiasing schemes, illustrative, non-exclusive examples of which are shownin FIG. 6 and include 1) Source-line row-wide write ‘0’, 2) Row-widewrite ‘0’ via gate tunneling method by port #1 or port #2, and 3)Bit-selective write ‘0’ by port #1 or port #2. Bit-selective write mayallow the write ‘0’ operation to be performed on a specific memory cellwithout affecting unselected memory cells in the array. Row-wide write‘0’ may be utilized for memory reset and/or erase for any particular rowand/or group of rows in array 81 and may be performed using the SLterminal that is common to both ports. Bit-selective write ‘0’ may beused for regular random memory address write operations.

Referring once again to FIG. 1 for a single memory cell 1 and FIG. 4 foran array 81 of memory cells, illustrative, non-exclusive examples of thebiasing conditions for a source-line row-wide write ‘0’ operation to row“a”, as shown in FIG. 6, are presented below. The source-line (SL)row-wide write ‘0’ operation on row “a” may be performed by applying anegative voltage to SL terminal 72 (row 72 a), a zero voltage to theremaining SL terminals of array 81 (rows 72 b-72 p), and a zero voltageto substrate terminal 78, WL1 terminal 70 (rows 70 a-70 p), BL1 terminal74 (columns 74 a-74 n), WL2 terminal 76 (rows 76 a-76 p), and BL2terminal 77 (columns 77 a-77 n).

Under these conditions, the p-n junctions (junction between 24 and 16)are forward-biased, evacuating any holes from floating body 24. In oneparticular non-limiting embodiment, about −1.2 volts may be applied toterminal 72 and about 0.0 volt may be applied to terminals 78, 70, 74,76 and 77. However, these voltage levels may vary, while maintaining therelative relationships between the charges applied, as described above.

The bias conditions for all the unselected cells are the same since thewrite ‘0’ operation only involves applying a negative voltage to the SLterminal 72 (thus to the entire row). As can be seen, the unselectedmemory cells will be in idle mode, with WL1, BL1, WL2, BL2 and SLterminals at about 0.0 volts.

Illustrative, non-exclusive examples of the biasing conditions for therow-wide write ‘0’ operation via the gate-tunneling method to row ‘a’ byport #1, as shown in FIG. 6, are presented below. The row-wide write ‘0’operation via the gate-tunneling method by port #1 may be performed byapplying a relatively higher (when compared to the source-line row-widewrite ‘0’ operation) negative voltage to WL1 terminal 70 (row 70 a), azero voltage to the remaining WL1 terminals in array 81 (rows 70 b-70p), and a zero voltage to substrate terminals 78, BL1 terminal 74(columns 74 a-74 n), SL terminal 72 (rows 72 a-72 p), WL2 terminal 76(rows 76 a-76 p), and BL2 terminal 77 (columns 77 a-77 n).

Under these conditions, charges that may be present within floating body24 will evacuate through insulator layer 62 to gate 60 and floating body24 will be placed in state ‘0’. WL1 terminal 70 for unselected cells 1that are not commonly connected to the selected cell will remaingrounded. In one particular non-limiting embodiment, for selected cell 1a potential of about −2.4 volts is applied to WL1 terminal 70 and apotential of about 0.0 volt is applied to substrate terminal 78, BL1terminal 74, SL terminal 72, WL2 terminal 76 and BL2 terminal 77.However, these voltage levels may vary.

Illustrative, non-exclusive examples of the biasing conditions for therow-wide write ‘0’ operation via gate-tunneling method to row “a” byport #2, as shown in FIG. 6, are presented below. The row-wide write ‘0’operation via gate-tunneling method by port #2 may be performed byapplying a relatively larger (when compared to the source-line row-widewrite ‘0’ operation) negative voltage to WL2 terminal 76 (76 a), a zerovoltage to the remaining WL2 terminals in array 81 (rows 76 b-76 p), anda zero voltage to substrate terminal 78, BL1 terminal 74 (columns 74a-74 n), SL terminal 72 (rows 72 a-72 p), WL1 terminal 70 (rows 70 a-70p), and BL2 terminal 77 (columns 77 a-77 n).

Under these conditions, charges that may be present within floating body24 will evacuate through insulator layer 66 to gate 64 and floating body24 will be placed in state ‘0’. WL2 terminal 76 for unselected cells 1that are not commonly connected to the selected cell will remaingrounded. In one particular non-limiting embodiment, for the selectedcell a potential of about −2.4 volts is applied to WL2 terminal 76 and apotential of about 0.0 volt is applied to substrate terminal 78, BL1terminal 74, SL terminal 72, WL1 terminal 70 and BL2 terminal 77.However, these voltage levels may vary.

The bias conditions for all the unselected cells are the same since thewrite ‘0’ operation only involves applying a negative voltage to the WLterminals 70/76 (thus to the entire row). As can be seen, the unselectedmemory cells will be in the idle mode, with WL1, BL1, WL2, BL2 and SLterminals at about 0.0 volts. Thus, the idle mode does not interrupt therow-wide write ‘0’ operation of the memory cells. Furthermore, theunselected memory cells will remain in idle mode during a row-wide write‘0’ operation.

Illustrative, non-exclusive examples of the biasing conditions for thebit-selective write ‘0’ operation on selected memory cell 1 aa by port#1, as shown in FIG. 6, are presented below. The bit-selective write ‘0’operation on selected memory cell 1 aa by port #1 may be performed byapplying a positive voltage to WL1 terminal 70 (row 70 a), a zerovoltage to the remaining WL1 terminals in array 81 (rows 70 b-70 p), anegative voltage to BL1 terminal 74 (column 74 a), a zero voltage to theremaining BL1 terminals in array 81 (columns 74 b-74 n), a zero orpositive voltage to SL terminal 72 (rows 72 a-72 p), a zero or negativevoltage to WL2 terminal 76 (rows 76 a-76 p), a zero voltage to BL2terminal 77 (columns 77 a-77 n), and a zero voltage to substrateterminal 78.

Under these conditions, the floating body 24 potential will increasethrough capacitive coupling from the positive voltage applied to WL1terminal 70. As a result of the floating body 24 potential increase andthe negative voltage applied to BL1 terminal 74, the p-n junction(junction between regions 24 and 18) will be forward-biased, evacuatingany holes from floating body 24.

The applied bias to selected WL1 terminal 70 and selected BL1 terminal74 may affect the states of the unselected memory cells 1 sharing thesame WL1 or BL1 terminal as the selected memory cell 1. To reduce thepotential for an undesired write ‘0’ disturb to other memory cells 1 inthe memory array 81, the applied potential may be optimized as follows:If the floating body 24 potential of state ‘1’ is referred to asV_(FB1), then the voltage applied to WL1 terminal 70 is configured toincrease the potential of floating body 24 by V_(FB1)/2, and −V_(FB1)/2may be applied to BL1 terminal 74. This will decrease the floating body24 potential change in the unselected cells in state ‘1’ sharing thesame BL1 terminal as the selected cell from V_(FB1) to V_(FB1)/2. Formemory cells 1 in state ‘0’ sharing the same WL1 terminal as theselected cell 1, unless the increase in floating body 24 potential issufficiently high (i.e., at least V_(FB)/3, see below), then n-p-nbipolar devices 132 and 133 will not be turned on and/or the base holdcurrent will be low enough that it does not result in an increase of thefloating body 24 potential over the time during which the writeoperation is carried out (write operation time).

In the memory cell of FIG. 1, it has been determined that a floatingbody 24 potential increase of V_(FB)/3 is low enough to suppress thefloating body 24 potential increase. A positive voltage may be appliedto SL terminal 72 to further reduce the undesired write ‘0’ disturb onother memory cells 1 in the memory array. The unselected cells willremain in idle mode, i.e. zero or negative voltage applied to WL1terminal 70 and zero voltage applied to BL1 terminal 74.

In one particular non-limiting embodiment, for the selected cell apotential of about 0.0 volts is applied to terminal 78, a potential ofabout −0.2 volts is applied to terminal 74, a potential of about +0.5volts is applied to terminal 70 (which will increase the potential ofthe floating body region 24 through capacitive coupling), and apotential of about 0.0 volts is applied to terminals 72, 76, and 77.However, these voltage levels may vary.

Illustrative, non-exclusive examples of the biasing conditions for thebit-selective write ‘0’ operation on selected memory cell 1 aa by port#2, as shown in FIG. 6, are presented below. The bit-selective write ‘0’operation on selected memory cell 1 aa by port #1 may be performed byapplying a positive voltage to WL2 terminal 76 (row 76 a), a zerovoltage to the remaining WL2 terminals in array 81 (rows 76 b-76 p), anegative voltage to BL2 terminal 77 (column 77 a), a zero voltage to theremaining BL2 terminals in array 81 (columns 77 b-77 n), a zero orpositive voltage to SL terminal 72 (rows 72 a-72 p), a zero or negativevoltage to WL1 terminal 70 (rows 70 a-70 p), a zero voltage to BL1terminal 74, and a zero voltage to substrate terminals 78.

Under these conditions, the floating body 24 potential will increasethrough capacitive coupling from the positive voltage applied to the WL2terminal 76. As a result of the floating body 24 potential increases andthe negative voltage applied to the BL2 terminal 77, the p-n junction(junction between regions 24 and 20) will be forward-biased, evacuatingany holes from floating body 24.

Similar to the bit-selective write ‘0’ operation on port #1, the appliedbias to selected WL2 terminal 76 and selected BL2 terminal 77 may affectthe states of the unselected memory cells 1 sharing the same WL2 or BL2terminal as the selected memory cell 1. To reduce the potential for anundesired write ‘0’ disturb to other memory cells 1 in the memory array81, the applied potential may be optimized as follows: If the floatingbody 24 potential of state ‘1’ is referred to as V_(FB1), then thevoltage applied to WL2 terminal 76 is configured to increase thepotential of floating body 24 by V_(FB1)/2, and −V_(FB1)/2 may beapplied to BL2 terminal 77. This will decrease the floating body 24potential change in the unselected cells in state ‘1’ sharing the sameBL2 terminal as the selected cell from V_(FB1) to V_(FB1)/2. For memorycells 1 in state ‘0’ sharing the same WL2 terminal as the selected cell1, unless the increase in floating body 24 potential is sufficientlyhigh (i.e., at least V_(FB)/3, see below), then the n-p-n bipolardevices 132 and 133 will not be turned on and/or the base hold currentwill be low enough that it does not result in an increase of thefloating body 24 potential over the time during which the writeoperation is carried out (write operation time).

In the memory cell of FIG. 1, it has been determined that a floatingbody 24 potential increase of V_(FB)/3 is low enough to suppress thefloating body 24 potential increase. A positive voltage may be appliedto SL terminal 72 to further reduce the undesired write ‘0’ disturb onother memory cells 1 in the memory array. The unselected cells willremain at idle mode, i.e. zero or negative voltage applied to WL2terminal 76 and zero voltage applied to BL2 terminal 77.

In one particular non-limiting embodiment, for selected cell 1 apotential of about 0.0 volts is applied to terminal 78, a potential ofabout −0.2 volts is applied to terminal 77, a potential of about +0.5volts is applied to terminal 76 (which will increase the potential ofthe floating body region 24 through capacitive coupling), and apotential of about 0.0 volts is applied to terminals 72, 70, and 74.However, these voltage levels may vary.

A write ‘1’ operation by either port #1 or port #2 may be performed onmemory cell 1 using any suitable method, process, and/or mechanism.Illustrative, non-exclusive examples of suitable mechanisms include animpact ionization mechanism and/or a band-to-band tunneling mechanism,as described for example in “A Design of a Capacitorless 1T-DRAM CellUsing Gate-Induced Drain Leakage (GIDL) Current for Low-power andHigh-speed Embedded Memory”, Yoshida et al., pp. 913-918, InternationalElectron Devices Meeting, 2003.

With continued reference to FIGS. 1 and 4, illustrative, non-exclusiveexamples of the biasing conditions for the band-to-band tunneling write‘1’ GIDL operation on selected memory cell 1 aa by port #1, as shown inFIG. 6, are presented below. The band-to-band tunneling write ‘1’ GIDLoperation to selected memory cell 1 aa by port #1 may be performed byapplying a zero voltage to substrate terminal 78, a negative voltage toWL1 terminal 70 (row 70 a), a zero voltage to the remaining WL1terminals in array 81 (rows 70 b-70 p), a positive voltage to BL1terminal 74 (column 74 a), a zero voltage to the remaining BL1 terminalsin array 81 (columns 74 b-74 n), zero voltage to SL terminal 72 (rows 72a-72 p), a zero or negative voltage to WL2 terminal 76 (rows 76 a-76 p),and a zero voltage to BL2 terminal 77 (columns 77 a-77 n).

The negative bias on WL1 terminal 70 and the positive bias on BL1terminal 74 will result in hole injection into floating body 24. Theunselected cells 1 will remain in the idle mode. In one particularnon-limiting embodiment, about 0.0 volts is applied to terminal 78,about +1.2 volts is applied to terminals 74, about −1.2 volts is appliedto terminal 70, and about 0.0 volts is applied to terminals 72, 76 and77. However, these voltage levels may vary.

Illustrative, non-exclusive examples of the biasing conditions for theband-to-band tunneling write ‘1’ GIDL operation on selected memory celllaa by port #2, as shown in FIG. 6, are presented below. The biasingconditions for the write ‘1’ operation by port #2 are substantiallysimilar to the biasing conditions for the write ‘1’ operation by port#1, except that the positive voltage is applied to BL2 terminal 77(column 77 a) of the selected memory cell instead of to BL1 terminal 74(74 a) of the selected memory cell, which instead has a zero or negativevoltage applied thereto; and the negative voltage is applied to WL2terminal 76 (row 76 a) instead to WL1 terminal 70 (row 70 a), whichinstead has a zero or negative voltage applied thereto. In oneparticular non-limiting embodiment, about 0.0 volts is applied toterminal 78, about +1.2 volts is applied to terminal 77, about −1.2volts is applied to terminal 76, and about 0.0 volts is applied toterminals 72, 70 and 74. However, these voltage levels may vary.

When performing the band-to-band tunneling write ‘1’ GIDL operation onselected memory cell laa by port #1 and/or port #2, unselected memorycells sharing the same row as the selected memory cell will have theirSL terminal 72 and BL1 (or BL2) terminal 74 (or 77) at about 0.0 voltsand their WL1 (or WL2) terminal 70 (or 76) at zero or negative voltage.Thus, the unselected memory cells are in idle mode. As a result, thestates of these unselected memory cells will remain unchanged.

For unselected memory cells sharing the same column as the selectedmemory cell, SL terminal 72 and WL1 (or WL2) terminal 70 (or 76) will beat about 0.0 volt and BL1 (or BL2) terminal 74 (or 77) will be at about+1.2 volts. Comparing with the holding operation bias condition, it canbe seen that cells sharing the same column (i.e. the same BL1/BL2terminals 74177) are in the holding operation. As a result, the statesof these memory cells will remain unchanged.

For unselected memory cells not sharing the same row or the same columnas the selected memory cell, the SL terminal 72, WL1/WL2 terminal 70/76and BL1/BL2 terminals 74/77 are at about 0.0 volts. Thus, these cellswill be in the idle mode. As a result, the idle mode and the holdingoperation do not interrupt the write l′ operation of the selected memorycell(s).

Illustrative, non-exclusive examples of the biasing conditions for thewrite ‘1’ operation on selected memory cell laa by port #1 using theimpact ionization method, as shown in FIG. 6, are presented below. Theimpact ionization write ‘1’ operation to selected memory cell laa byport #1 may be performed by applying a zero voltage to substrateterminal 78, a positive voltage to BL1 terminal 74 (column 74 a), a zerovoltage to the remaining BL1 terminals 74 in array 81 (columns 74 b-74n), a positive voltage to WL1 terminal 70 (row 70 a), a zero voltage tothe remaining WL1 terminals 70 in array 81 (rows 70 b-70 p), and a zerovoltage to SL terminal 72 (rows 72 a-72 p), WL2 terminal 76 (rows 76a-76 p), and BL2 terminal 77 (columns 77 a-77 n).

If the potential of bit line region 18 is equal to or higher than thedifference between the potential of gate 60 and the threshold voltage, apinch-off region may be formed near bit line region 18. A large electricfield will be developed in this pinch-off region, accelerating theelectrons flowing from source line region 16 to bit line region 18.These energetic electrons will collide with atoms in the semiconductorlattice, which will generate hole-electron pairs in the vicinity of thejunction. The electrons will be swept into bit line region 18 by theelectric field and become a bit line current, while the holes will beswept into the floating body region, becoming the hole charge thatcreates the state ‘1’.

In one particular non-limiting embodiment, to perform a write ‘1’operation to the selected cell 1 by port #1, a potential of about 0.0volts is applied to terminal 78, a potential of about +1.2 volts isapplied to terminal 74, a potential of about +1.2 volts is applied toterminal 70, and a potential of about 0.0 volts is applied to terminals72, 76 and 77. For the unselected cells not sharing the same WL1terminal or BL1 terminal with the selected memory cell 1, about 0.0volts is applied to terminal 72, about 0.0 volts is applied to terminal74, about 0.0 volts is applied to terminal 70, about 0.0 volt is appliedto terminal 78, about 0.0 volts is applied to terminal 76, and about 0.0volts is applied to terminal 77. However, these voltage levels may vary.

Illustrative, non-exclusive examples of the biasing conditions for thewrite ‘1’ operation on selected memory cell laa by port #2 using theimpact ionization method, as shown in FIG. 6, are presented below. Thebiasing conditions for the write 1′ operation by port #2 aresubstantially similar to the biasing conditions for the write ‘1’operation by port #1, except that the positive voltage is applied to BL2terminal 77 (column 77 a) and WL2 terminal 76 (row 76 a) of the selectedmemory cell instead of to BL1 terminal 74 (column 74 a) and WL1 terminal70 (row 74 a), which instead have a zero voltage applied thereto.

In one particular non-limiting embodiment, to perform a write ‘1’operation to the selected cell 1 by port #2, a potential of about 0.0volts is applied to terminal 72, a potential of about 0.0 volt isapplied to terminal 74, a potential of about 0.0 volts is applied toterminal 70, a potential of about 0.0 volts is applied to terminal 78, apotential of about +1.2 volts is applied to terminal 76, and a potentialof about +1.2 volts is applied to terminal 77. However, these voltagelevels may vary.

FIGS. 8 and 9 are three-dimensional schematic representations ofadditional illustrative, non-exclusive examples of memory cells 1according to the present disclosure, while FIG. 10 is a top view of thememory cell of FIG. 8. The memory cells of FIGS. 8-10 are functionallysimilar to dual-port memory cell 1 of FIGS. 1-4 but includethree-dimensional fin-type memory cells 1, which also may be referred toherein as memory cells 1 and/or cells 1. Fin-type memory cells 1 includea fin structure 51 that is fabricated on a substrate 12 having a firstconductivity type (such as p-type conductivity type) so as to extendfrom a top surface of the substrate to form a three-dimensionalstructure, with fin 51 extending substantially perpendicularly to, andabove, the top surface of substrate 12. Fin 51, which also may bereferred to herein as fin structure 51 and/or elongate fin structure 51,includes first, second and third regions 18, 16, and 20, respectively,having the second conductivity type. A floating body region 24 isbounded by the top surface of fin 53, first region 18, second region 16,and third region 20 and insulating layers 28 (shown in FIG. 10).

The floating body region 24 is conductive having a first conductivitytype (such as p-type conductivity type) and may be formed using anysuitable process and/or method, illustrative, non-exclusive examples ofwhich include an ion implantation process and/or epitaxial growth. Fin51 may be formed from any suitable material, illustrative, non-exclusiveexamples of which include silicon, germanium, silicon germanium, galliumarsenide, carbon nanotubes, or other semiconductor materials. The cell 1also includes an insulator layer 22, which may be formed from anysuitable insulating, or dielectric, material, illustrative,non-exclusive examples of which are discussed in more detail herein.

Memory cell 1 further may include gates 60 and 64 on two opposite sidesof floating body region 24, as shown in FIG. 8. Alternatively, gates 60and 64 may enclose three sides of floating body region 24 as shown inFIG. 9. Gates 60 and 64 are insulated from floating body region 24 byinsulating layers 62 and 66, respectively. Gates 60 are positionedbetween the first and second regions 18, 16 adjacent to the floatingbody region 24 and gates 64 are positioned between the second and thirdregions 16, 20, adjacent to the floating body region 24. Gates 60 and 64are spaced apart along a longitudinal axis of fin structure 51.

Similar to dual-port memory cell 1, fin-type memory cells 1 includeseveral terminals: word line #1 (WL1) terminal 70, word line #2 (WL2)terminal 76, source line (SL) terminal 72, bit line #1 (BL1) terminal74, bit line #2 (BL2) terminal 77 and substrate terminal 78. Terminal 70is connected to the gate 60. Terminal 76 is connected to the gate 64.Terminal 72 is connected to second region 16, terminal 74 is connectedto first region 18, terminal 77 is connected to third region 20, andterminal 78 is connected to substrate 12.

Similar to dual-port memory cells 1, fin-type memory cells 1 may includetwo ports and the response of fin-type memory cells 1 to various biasingconditions is substantially similar to the response of dual-port memorycells 1 to similar biasing conditions. These biasing conditions andresponses are discussed in more detail herein with reference to FIGS. 5and 6.

Dual-port memory cells 1 of FIGS. 1-4 and/or fin-type memory cells 1 ofFIGS. 8-10 are shown including two ports, namely, port #1 and port #2.However, it is within the scope of the present disclosure that memorycells 1 and/or memory cells 9 may include any suitable number of ports,including 3 ports, 4 ports, 5 ports, 6 ports, 8 ports, 10 ports, or morethan 10 ports. FIG. 11 is an illustrative, non-exclusive example ofanother embodiment of memory cell 1 according to the present disclosure.The memory cell of FIG. 11 includes four ports and also may be referredto herein as a quad-port memory cell 1, a memory cell 1, a cell 1,and/or a quad-port memory 1. Quad-port memory cell 1 may be fabricatedon a substrate 108 of a first conductivity type, such as p-typeconductivity type, for example. Substrate 108 may include any suitablesubstrate, an illustrative, non-exclusive example of which includes anSOI substrate. Similarly, substrate 108 may be formed from any suitablesemiconductor material, illustrative, non-exclusive examples of whichinclude silicon, germanium, silicon germanium, gallium arsenide, carbonnanotubes, and/or other semiconductor materials.

Substrate 108 includes and/or has formed therein a buried insulatorlayer 122. Buried insulator layer 122 may include any suitabledielectric, or electrically insulating, material, an illustrative,non-exclusive example of which includes silicon dioxide.

A floating body region 124 of the first conductivity type, such asp-type, for example, is bounded on top by surface 104 and regions 110,112, 114, 116, and 118 of a second conductivity type. Floating body 124may have the same doping as substrate 108 in some embodiments or adifferent doping, if desired, in other embodiments, as a matter ofdesign choice. Regions 110, 112, 114, 116, and 118 may be formed by anysuitable process, illustrative, non-exclusive examples of which includean ion implantation process and/or a solid state diffusion process.

The regions 112 and 118 are formed such that they reach the buriedinsulator layer 122. Thus, regions 112 and 118 insulate floating body124 from its neighboring floating body 124 of adjacent cells whenmultiple cells 1 are joined in an array. On the other hand, the regions110, 114, and 116 are formed such that they do not reach the buriedinsulator layer 122. This provides for floating body 124, which is usedto store the memory state, to be shared and thus can to be accessedthrough multiple ports (four ports in this example).

Floating body 124 also may be bounded on one or more sides by insulatinglayers (not shown in FIG. 8). The insulating layers may insulate cell 1from neighboring cells 1 when multiple cells 1 are joined to form amemory array.

Gates 160, 162, 164, and 166 may be positioned above surface 104. Gate160 is insulated from surface 104 by an insulating layer 150 and ispositioned in between regions 112 and 114. The gate 162 is insulatedfrom surface 104 by an insulating layer 152 and is positioned in betweenregions 114 and 110. Gate 164 is insulated from surface 104 by aninsulating layer 154 and is positioned in between regions 110 and 116.Gate 166 is insulated from surface 104 by an insulating layer 156 and ispositioned in between regions 116 and 118.

Insulating layers 150, 152, 154, and/or 156 may be formed from anysuitable insulator and/or dielectric material using any suitable processand/or method. Illustrative, non-exclusive examples of materials thatmay be included in insulating layers 150, 152, 154, and/or 156 accordingto the present disclosure include silicon oxide high-K dielectricmaterials, tantalum peroxide, titanium oxide, zirconium oxide, hafniumoxide, and/or aluminum oxide.

Similarly, gates 160, 162, 164, and/or 166 may be formed from anysuitable material using any suitable process and/or method.Illustrative, non-exclusive examples of materials that may be includedin gates 160, 162, 164, and/or 166 include polysilicon, metal gateelectrode materials, tungsten, tantalum, titanium and/or their nitrides.

Cell 1 further includes word line #1 (WL1) terminal 180 electricallyconnected to gate 160, word line #2 (WL2) terminal 182 electricallyconnected to gate 162, word line #3 (WL3) terminal 184 electricallyconnected to gate 164, word line #4 (WL4) terminal 186 electricallyconnected to gate 166, source line (SL) terminal 170 electricallyconnected region 110, bit line #1 (BL1) terminal 172 electricallyconnected to region 112, bit line #2 (BL2) terminal 174 electricallyconnected to region 114, bit line #3 (BL3) terminal 176 electricallyconnected to region 116, bit line #4 (BL4) terminal 178 electricallyconnected to region 118, and substrate terminal 188 electricallyconnected to substrate 108.

These terminals define a plurality of ports that may form a portion ofquad-port memory cell 1. With this in mind, WL1 terminal 180 and BL1terminal 172 also may be referred to herein as ‘port #1’, WL2 terminal182 and BL2 terminal 174 also may be referred to herein as ‘port #2’,WL3 terminal 184 and BL3 terminal 176 also may be referred to herein‘port #3’, and WL4 terminal 186 and BL4 terminal 178 also may bereferred to herein ‘port #4’.

It is within the scope of the present disclosure that additional portsmay be constructed in a similar manner (i.e., by forming additionalregions of a second conductivity type and positioning an additional gateabove the surface and in between two regions of the second conductivitytype). For an n-port memory cell, the number of gates and the number ofbit lines are equal to n, while the number of regions of the secondconductivity type is equal to (n+1). All regions of a secondconductivity type and gates in a multi-port memory cell according to thepresent disclosure will be coupled to the same floating body region 124.

FIG. 12 is a schematic representation of an illustrative, non-exclusiveexample of a second embodiment 2 of memory cell 9 according to thepresent disclosure. The embodiment of FIG. 12 also may be referred toherein as dual-port memory cell 2, memory cell 2, and/or cell 2. Memorycell 2 is substantially similar to dual-port memory cell 1 of FIGS. 1-4but includes a plurality of insulating layers 26 between adjacent memorycells that may be present within an array of memory cells to isolate theadjacent memory cells from one another, as shown. In addition, memorycell 2 does not include buried insulator layer 22 between floating bodyregion 24 and substrate 12.

In FIG. 12, floating body region 24 having a second conductivity type,such as a p-type conductivity type, is bounded by surface 14, first,second and third regions 18, 16, and 20, respectively of the firstconductivity type, insulating layers 26, and substrate 12. Floating bodyregion 24 may be formed using any suitable process and/or method,illustrative, non-exclusive examples of which are discussed in moredetail herein.

Insulating layers 26, which also may be referred to herein as shallowtrench isolation (STI) 26, may be formed from any suitable insulatingand/or dielectric material, illustrative, non-exclusive examples ofwhich are discussed in more detail herein. Insulating layers 26 mayinsulate cell 2 from neighboring cells 2 when multiple cells 2 arejoined in an array 81 to form a memory device 10 as illustrated in FIG.13.

The memory states of memory cell 2 are represented by the charge infloating body region 24. If cell 2 has holes stored in floating bodyregion 24, then the memory cell 2 will have a lower threshold voltage(gate voltage where transistor is turned on) compared to when cell 2does not store holes in floating body region 24.

FIGS. 14 and 15 provide illustrative, non-exclusive examples ofequivalent circuit representations of memory cell 2. As shown in FIG.14, memory cell 2 includes n-p-n bipolar devices 230, 231, and 232.Bipolar device 230 is formed by substrate 12, floating body region 24,and BL1 region 18, bipolar device 231 is formed by substrate 12,floating body region 24, and SL region 16, and bipolar device 232 isformed by substrate 12, floating body region 24, and BL2 region 20.Bipolar devices 230, 231, and 232 are connected in parallel with acommon substrate 12 and floating body region 24.

As shown in FIG. 15, memory cell 2 also includes two additional bipolardevices 233 (formed by BL1 region 18, floating body region 24, and SLregion 16) and 234 (formed by BL2 region 20, floating body region 24,and SL region 16) connected in series, where the SL region 16 and thefloating body 24 is shared between the two bipolar devices. In addition,memory cell 2 also includes two field effect transistors 235 (formed byBL1 region 18, gate 60 connected to WL1 terminal 70, and SL region 16)and 236 (formed by BL2 region 20, gate 64 connected to WL2 terminal 76,and SL region 16) connected in series, where the SL region 16 and thefloating body 24 is shared between the two field effect transistors.Operation of memory cell 2 is described below.

Memory cells 2 of FIG. 12 and/or array 81 of FIG. 13 may be operated ina plurality of states and/or modes and/or may be subject to a pluralityof operating conditions, or operations, which may include a plurality ofbiasing conditions for memory cells 2. Illustrative, non-exclusiveexamples of operations for memory cells 2 according to the presentdisclosure include a holding, or refresh, operation, a read port #1 onlyoperation, a read port #2 only operation, a simultaneous read port #1and port #2 operation, a row-wide write ‘0’ operation, a bit-selectivewrite ‘0’ on port #1 operation, a bit-selective write ‘0’ on port #2operation, a write ‘1’ GIDL on port #1 operation, a write ‘1’ GIDL onport #2 operation, a write ‘1’ on port #1 by impact ionizationoperation, and/or a write 1′ on port #2 by impact ionization operation.

Illustrative, non-exclusive examples of biasing conditions for the aboveoperations are shown in FIGS. 16-19. In FIGS. 16-19, the first columndescribes the operation that is being performed upon memory cell 2 ofFIG. 12 and/or upon one or more memory cells “2 xy” of FIG. 13, wherethe “x” indicates the row 80 (a through p) in which the memory cell(s)is/are located within array 81 and the “y” indicates the column 79 (athrough n) in which the memory cell(s) is/are located within array 81.In addition, the second column describes the memory cell(s) upon whichthe operation is being performed. “All” indicates that the givenoperation (and, by extension, the given biasing conditions) may beapplied to all of memory cells 2 within array 81 of FIG. 13. When agiven operation may be applied only to one or more selected cell(s)and/or selected row(s) of cells within array 81, “Selected Cell(s)”and/or “Selected Row(s)” may indicate the biasing conditions that may beapplied to the selected cell (an illustrative, non-exclusive example ofwhich is cell “2 aa” of FIG. 13) and/or to the selected row of cells (anillustrative, non-exclusive example of which is row “a” (which mayinclude all memory cells 2 in row “a” of FIG. 13)). Similarly“Unselected Cell(s)” may indicate the biasing conditions that may beapplied to the unselected cells upon which the given operation is notperformed.

With continued reference to FIGS. 16-19, columns 3-8 list the biasingconditions that may be applied to terminals 78, 74, 70, 72, 76, and/or77 of the selected and/or unselected memory cells for the givenoperation. As an illustrative, non-exclusive example, and with referenceto FIGS. 13 and 17, the read port #1 only operation may be performed onselected cell “2 aa” by applying a zero or positive voltage to substrateterminal 78 a, a Positive2 (which is less than the Positive1) voltage toBL1 terminal 74 a, a Positive1 voltage to WL1 terminal 70 a, a zerovoltage to SL terminal 72 a, a zero or negative voltage to WL2 terminal76 a, and a zero voltage to BL2 terminal 77. In addition, all unselectedmemory cells within array 81 of FIG. 13 will be biased by the givenvoltage. This includes applying a zero or positive voltage to unselectedsubstrate terminals 78 b-78 p, a zero voltage to unselected BL1terminals 74 b-74 n, a zero voltage to unselected WL1 terminals 70 b-70p, a zero voltage to unselected SL terminals 72 b-72 p, a zero ornegative voltage to unselected WL2 terminals 76 b-76 p, and a zerovoltage to unselected BL2 terminals 77 b-77 n.

As another illustrative, non-exclusive example, and with reference toFIGS. 13 and 18, the row-wide write ‘0’ operation may be performed onselected row “a” by applying a zero or a positive voltage to substrateterminal 78 a, a zero or negative voltage to BL1 terminal 74 a, a zeroor negative voltage to WL1 terminal 70 a, a negative voltage to SLterminal 72 a, a zero or negative voltage to WL2 terminal 76 a, and azero or negative voltage to BL2 terminal 77 a. In addition, allunselected memory cells “2 xy” within array 81 of FIG. 13 will be biasedby the voltage shown in FIG. 18. This includes applying a zero orpositive voltage to unselected substrate terminals 78 b-78 p, a zero ornegative voltage to unselected BL1 terminals 74 b-74 n, a zero ornegative voltage to unselected WL1 terminals 70 b-70 p, a zero voltageto unselected SL terminals 72 b-72 p, a zero or negative voltage tounselected WL2 terminals 76 b-76 p, and a zero or negative voltage tounselected BL2 terminals 77 b-77 n.

The above examples are given for illustration purposes only and it iswithin the scope of the present disclosure that any suitable selectedmemory cell “2 xy” and/or any suitable selected row “x” of memory cellswithin array 81 may be biased by the biasing conditions associated withany suitable one of the operations described in FIGS. 16-19. Inaddition, it is also within the scope of the present disclosure that thevoltage associated with each of the biasing conditions listed in FIGS.16-19 may include any suitable magnitude and that this magnitude mayvary depending on a variety of factors, illustrative, non-exclusiveexamples of which include the doping levels and/or charge carrierconcentrations present within any suitable portion(s) and/or region(s)of memory cell 2 and/or the size, lengths scales, and/or geometry ofmemory cell 2. Thus, while illustrative, non-exclusive examples of thebiasing voltages that may be utilized with each of the operationsdescribed in FIGS. 16-19 are shown in parenthesis therein, these voltagevalues may vary without departing from the scope of the presentdisclosure.

With continued reference to FIG. 13 for an illustrative, non-exclusiveexample of array 81 of memory cells 2, FIG. 16 provides illustrative,non-exclusive examples of biasing conditions that may be utilized toperform the holding and/or refresh operation on all of the memory cellspresent within array 81. When floating body region 24 includes apositive charge, the positive charge stored in floating body region 24may decrease over time. This decrease may be due to p-n diode leakagefrom the p-n diodes formed by floating body 24 and regions 16, 18, 20,and substrate 12 and/or due to charge recombination. A unique capabilityof memory cell 2 is that it may provide for performing the holdingoperation in parallel to all memory cells 2 in array 81 by applying thebiasing voltages shown in FIG. 16.

During the holding operation, and as discussed in more detail herein, afraction of the bipolar transistor current will then flow into floatingbody region 24 (usually referred to as the base current) and maintainthe state ‘1’ data. The efficiency of the holding operation may beenhanced by designing the bipolar devices 230, 231, 232 formed onsubstrate 12, floating body region 24, and/or regions 18/16/20 to below-gain bipolar devices, where the bipolar gain is defined as the ratioof the collector current flowing out of substrate terminal 78 to thebase current flowing into the floating body region 24.

For memory cells in state ‘0’ data, the bipolar devices 230, 231, 232will not be turned on, and consequently no base hole current will flowinto floating body region 24. Therefore, memory cells in state ‘0’ willremain in state ‘0’.

The holding operation may be performed in a mass, parallel manner as thesubstrate terminal 78 (functioning as back bias terminal) is typicallyshared by all the cells 2 in memory array 81, or at least by multiplecells 2 in a segment of array 81. Substrate terminal 78 also may besegmented to allow independent control of the applied bias to a selectedportion of memory array 81. Also, because substrate terminal 78 is notused for memory address selection, no memory cell access interruptionoccurs due to the holding operation.

In another embodiment, a periodic pulse of a positive voltage may beapplied to substrate terminal 78, as opposed to applying a constantpositive bias, in order to reduce the power consumption of memory cells2. The state of memory cell 2 may be maintained by refreshing the chargestored in floating body region 24 during the period over which thepositive voltage pulse is applied to the back bias terminal (i.e.,substrate terminal 78). As an illustrative, non-exclusive example, FIG.20 shows multiplexers 42 that may determine the bias applied tosubstrate terminal 78, where the control signal could be a clock signal40 or, as will be described later, determined by different operatingmodes. The positive input signals could be the power supply voltage Vcc(FIG. 20) or a different positive bias could be generated by voltagegenerator circuitry 44 (see FIG. 21).

The holding/standby operation also results in a larger memory window byincreasing the amount of charge that may be stored in floating bodyregion 24. Without the holding/standby operation, the maximum potentialthat may be stored in floating body region 24 may be limited to the flatband voltage V_(FB) as the junction leakage current to regions 16, 18and 20 increases exponentially at floating body potential greater thanV_(FB). However, by applying a positive voltage to substrate terminal78, the bipolar action results in a hole current flowing into floatingbody region 24, compensating for the junction leakage current betweenfloating body region 24 and regions 16, 18 and 20. As a result, themaximum charge V_(MC) stored in floating body region 24 may be increasedby applying a positive bias to the substrate terminal 78.

A plot of the maximum floating body potential (V_(MC)) as a function ofthe potential that is applied to substrate terminal 78 is shown in FIG.22. The increase in the maximum charge stored in the floating body 24provides for a larger memory window when using memory cells 2 whencompared to more conventional memory cells.

FIG. 23 shows a floating body region relative net current for differentfloating body region potentials as a function of the voltage applied tosubstrate terminal 78 with BL1, WL1, SL, WL1 and BL2 terminals 74, 70,72, 76 and 77 grounded. When zero voltage is applied to substrateterminal 78, no bipolar current is flowing into floating body 24 and, asa result, the stored charge will leak over time. When a positive voltageis applied to substrate terminal 78, hole current will flow intofloating body region 24 and balance the junction leakage current toregions 16, 18 and 20. The junction leakage current is determined by thepotential difference between floating body 24 and regions 16, 18 and 20,while the bipolar current flowing into floating body 24 is determined byboth the substrate terminal 78 potential and the floating body 24potential. As indicated in FIG. 23, for different floating bodypotentials, at a certain substrate terminal 78 potential, V_(HOLD), thecurrent flowing into floating body 24 is balanced by the junctionleakage between floating body 24 and regions 16, 18 and 20. Thedifferent floating body 24 potentials represent different charges usedto represent different states of memory cell 2. Thus, different memorystates may be maintained by using the holding/standby operationdescribed herein.

The charge stored in floating body region 24 of memory cell 2 may besensed by monitoring the cell current of memory cell 2. If cell 2 is ina state ‘1’ having holes in floating body region 24, then the memorycell will have a lower threshold voltage (gate voltage where thetransistor is turned on), and consequently a higher cell current,compared to if cell 2 is in a state ‘0’ having no holes in floating bodyregion 24. Thus, read circuitry and a reference generator similar tothat discussed in more detail herein with reference to FIG. 7 and memorycell 1 may be used to determine the data state of memory cell 2. Theoperation of the read circuitry and/or reference generator to determinethe data state of memory cell 2 is substantially similar to thatutilized to determine the data state of memory cell 1.

FIG. 17 provides illustrative, non-exclusive examples of biasingconditions that may be utilized to read the data state of memory cell 2of FIG. 12 and/or a selected memory cell “2 xy” in array 81 of FIG. 13.These include biasing conditions for the read port #1 only operation,the read port #2 only operation, and/or the simultaneous read port #1and port #2 operation. In FIG. 17, “Positive2” indicates a positivevoltage that is less than another positive voltage, “Positive 1,” thatmay be applied to another terminal of memory cell 2.

As a result of the bias conditions described in FIG. 17, the unselectedmemory cells will be at holding mode, maintaining the states of therespective floating body regions 24 thereof. Furthermore, the holdingoperation does not interrupt the read operation of the selected memorycell. In addition, the read port #1 only operation may be performed on afirst selected memory cell simultaneously with performing the read port#2 only operation on a second selected memory cell. As an illustrative,non-exclusive example, the read port #1 only operation may be performedon first selected memory cell “2 aa” simultaneously with the read port#2 operation being performed on second selected memory cell “2 bb.”

FIG. 18 provides illustrative, non-exclusive examples of biasingconditions that may be utilized to write a ‘0’ to memory cell 2 of FIG.12 and/or to a selected memory cell “2 xy” and/or a selected row ofmemory cells “x” in array 81 of FIG. 13. These include biasingconditions for the row-wide write ‘0’ operation, the bit-selective write‘0’ on port #1 operation, and/or the bit-selective write ‘0’ on port #2operation. In the row-wide write ‘0’ operation, an entire selected rowin array 81 is written with ‘0’s, while in the bit-selective write ‘0’operations, a selected memory cell, or cells, is written with a ‘0’without affecting unselected memory cells within array 81.

The row-wide write ‘0’ may be utilized for memory reset or erase for anyparticular row or group of rows in array 81 and may be accomplished viaSL terminal 72 that is common to both ports. The bit-selective write ‘0’may be useful for regular random memory address write operations and maybe performed via either port #1 or port #2.

When performing the row-wide write ‘0’ operation, a negative voltage maybe applied to SL terminal 72, a zero or negative voltage may be appliedto WL terminal 70, a zero or positive voltage may be applied tosubstrate terminal 78, while a zero voltage may be applied to BL1terminal 74, WL1 terminal 70, WL2 terminal 76 and BL2 terminal 77. TheSL terminal 72 for the unselected cells 2 that are not commonlyconnected to the selected cell will remain grounded. Under theseconditions, the p-n junctions (junction between 24 and 16) areforward-biased, evacuating any holes from floating body 24. In addition,the unselected memory cells will be in holding operation. Thus, theholding operation does not interrupt the write ‘0’ operation of memorycells 2. Furthermore, the unselected memory cells will remain in holdingoperation during the write ‘0’ operation.

A column-wide write ‘0’ operation also may be performed by applying anegative voltage to a selected BL terminal 74 and/or 77, with zero orpositive voltage being applied to the substrate terminal, and zerovoltage being applied to the WL terminals and SL terminal. Under theseconditions, the p-n junctions (junction between 24 and 18 or 20,depending on where the negative voltage is being applied to) of allcells sharing the selected bit line terminal will be forward-biased. Asa result, all cells in a column sharing the selected bit line terminalwill be written to state ‘0’.

The bit-selective write ‘0’ operation to cell 2 may be performed byeither port #1 or port #2 at any given time but not by bothsimultaneously. Furthermore, during a write operation, the other portcannot perform a read operation and vice versa. A write operation has tobe completed before a read operation by either port may commence or aread operation must be completed before a write operation by either portcan commence. See descriptions below for details on the write contentionavoidance.

During the bit-selective write ‘0’ on port #1 operation, the floatingbody region potential will increase through capacitive coupling from thepositive voltage applied to the WL1 terminal 70. As a result of thefloating body 24 potential increase and the negative voltage applied tothe BL1 terminal 74, the p-n junction (junction between 24 and 18) isforward-biased, evacuating any holes from floating body region 24. Thebias applied to selected WL1 terminal 70 and selected BL1 terminal 74may affect the states of the unselected memory cells 2 sharing the sameWL1 or BL1 terminal as the selected memory cell 2. To reduce thepotential for an undesired write ‘0’ disturb to other memory cells 2 inmemory array 81, the applied potential may be optimized as discussed inmore detail herein with reference to memory cells 1.

During the bit-selective write ‘0’ on port #2 operation, the floatingbody region potential will increase through capacitive coupling from thepositive voltage that is applied to the WL2 terminal 76. As a result ofthe floating body 24 potential increase and the negative voltage appliedto the BL2 terminal 77, the p-n junction (junction between 24 and 20) isforward-biased, evacuating any holes from floating body region 24. Thebias applied to selected WL2 terminal 76 and selected BL2 terminal 77may affect the states of the unselected memory cells 2 sharing the sameWL2 or BL2 terminal as the selected memory cell 2 and may be optimizedas discussed in more detail herein. When performing the bit-selectivewrite ‘0’ on port #2 operation, the unselected cells will remain atholding state.

During the write ‘0’ operations for memory cell 2 described above, thepositive back bias applied to the substrate terminal 78 of memory cells2 maintains the states of the unselected cells 2, especially thosesharing the same row or column as the selected cell, as the biascondition applied to the selected memory cell can potentially alter thestates of the unselected memory cells 2 without the intrinsic bipolardevices 230, 231, and 232 (formed by floating body 24, and regions 18,16, 20, respectively) re-establishing the equilibrium condition.Furthermore, the holding operation does not interrupt the write ‘0’operation of the memory cells 2.

FIG. 19 provides illustrative, non-exclusive examples of biasingconditions that may be utilized to write a ‘1’ to memory cell 2 of FIG.12 and/or to a selected memory cell “2 xy” in array 81 of FIG. 13. Theseinclude biasing conditions for the write ‘1’ GIDL on port #1 operation,the write ‘1’ GIDL on port #2 operation, the write ‘1’ on port #1 byimpact ionization operation, and/or the write ‘1’ on port #2 by impactionization operation. The write ‘1’ operation by either port #1 or port#2 may be performed on memory cell 2 through an impact ionizationmechanism or a band-to-band tunneling mechanism, as described forexample in “A Design of a Capacitorless 1T-DRAM Cell Using Gate-InducedDrain Leakage (GIDL) Current for Low-power and High-speed EmbeddedMemory”, Yoshida et al., pp. 913-918, International Electron DevicesMeeting, 2003.

When performing the write GIDL on port #1 operation, the negative biason WL1 terminal 70 and the positive bias on BL1 terminal 74 will resultin hole injection into floating body 24. The positive bias applied tosubstrate terminal 78 will maintain the resulting positive charge onfloating body 24 as discussed above, and the unselected cells 2 willremain at the holding mode. The positive bias applied to substrateterminal 78 employed for the holding operations does not interrupt thewrite ‘1’ operation of the selected memory cell(s).

When performing the write GIDL on port #2 operation, the negative biason WL2 terminal 76 and the positive bias on BL2 terminal 77 will resultin hole injection to the floating body 24. The positive bias applied tothe substrate terminal 78 will maintain the resulting positive charge onthe floating body 24 as discussed above, and the unselected cells 2 willremain at the holding mode. The positive bias applied to substrateterminal 78 employed for the holding operations does not interrupt thewrite 1′ operation of the selected memory cell(s).

During the write ‘1’ by port #1 operation using the impact ionizationmethod, if the potential of bit line region 18 is equal to or higherthan the difference between the gate 60 potential and the thresholdvoltage, a pinch-off region will be formed near the bit line region 18.A large electric field will be developed in the pinch-off region,accelerating the electrons flowing from source line region 16 to bitline region 18. The energetic electrons will collide with atoms in thesemiconductor lattice, which will generate hole-electron pairs in thevicinity of the junction. The electrons will be swept into bit lineregion 18 by the electric field and become the bit line current, whilethe holes will be swept into floating body region 24, becoming the holecharge that creates the state ‘1’.

During the write ‘1’ by port #2 operation using the impact ionizationmethod, if the potential of bit line region 20 is equal to or higherthan the difference between the gate 64 potential and the thresholdvoltage, a pinch-off region will be formed near the bit line region 20.A large electric field will be developed in the pinch-off region,accelerating the electrons flowing from the source line region 16 to bitline region 20. The energetic electrons will collide with atoms in thesemiconductor lattice, which will generate hole-electron pairs in thevicinity of the junction. The electrons will be swept into bit lineregion 20 by the electric field and become the bit line current, whilethe holes will be swept into the floating body region, becoming the holecharge that creates the state ‘1’.

FIGS. 24-25 are three-dimensional schematic representations ofadditional illustrative, non-exclusive examples of memory cells 2according to the present disclosure, while FIG. 26 is a top view of thememory cell of FIG. 24. Memory cells 2 of FIGS. 24-26 are functionallyequivalent to memory cells 2 of FIGS. 12-15, include the same terminalsas memory cells 2 of FIGS. 12-15, and include a fin structure 51 havinga second conductivity type (such as p-type conductivity type) fabricatedon substrate 12 having a first conductivity type (such as n-typeconductivity type) so as to extend from a top surface of the substrateto form a three-dimensional structure, with fin 51 extendingsubstantially perpendicularly to, and above the top surface of,substrate 12.

Fin structure 51 includes first, second and third regions 18, 16, 20having the first conductivity type. The floating body region 24 isbounded by the top surface of fin 51, first, second and third regions18, 16, 20 and insulating layers 26 (insulating layers 26 may be seen inthe top view of FIG. 26). Insulating layers 26 insulate cell 2 fromneighboring cells 2 when multiple cells 2 are joined to make memorydevice 10 (such as is schematically illustrated by array 81 of FIG. 13).Floating body region 24 may be formed using any suitable process and/ormethod, including those that are discussed in more detail herein. Fin 51may be formed from any suitable material, illustrative, non-exclusiveexamples of which are discussed in more detail herein.

Memory cell 2 of FIGS. 24-26 further may include gates 60 and 64 on twoopposite sides of floating body region 24 as shown in FIG. 24.Alternatively, gates 60 and 64 may enclose three sides of floating bodyregion 24, as shown in FIG. 25. Gates 60 and 64 are insulated fromfloating body 24 by insulating layers 62 and 66, respectively. Gates 60are positioned between the first and second regions 18, 16, adjacent tofloating body 24 and gates 64 are positioned between the second andthird regions 16, 20, adjacent to floating body 24.

Similar to memory cell 1 of FIG. 11, memory cell 2 may include and/or beextended to include any suitable number of ports and also may bereferred to herein as multi-port memory cells 2. Illustrative,non-exclusive examples of multi-port memory cells 2 according to thepresent disclosure include multi-port memory cells with 2 ports, 3ports, 4 ports, 5 ports, 6 ports, 7 ports, 8 ports, 9 ports, 10 ports,or more than 10 ports.

An illustrative, non-exclusive example of a multi-port memory cell 2, inthe form of a quad-port memory cell 2, is shown in FIG. 27. Quad-portmemory cell 2 is substantially similar to quad-port memory cell 1 ofFIG. 11 but also includes insulator layers 126, which insulate quad-portmemory cells 2 from neighboring quad-port memory cells 2 when thequad-port memory cells are arranged in an array. In addition, quad-portmemory cell 2 is formed on a substrate 108, illustrative, non-exclusiveexamples of which are discussed in more detail herein, that does notinclude buried insulator layer 122 of quad-port memory cell 1 of FIG.11.

FIG. 28 provides a schematic representation of an illustrative,non-exclusive example of a third embodiment 3 of a memory cell 9according to the present disclosure. The embodiment of FIG. 28 may bereferred to herein as dual-port memory cell 3, memory cell 3, and/orcell 3. Memory cell 3 is substantially similar to memory cell 1 of FIGS.1-11 but includes buried layer 23 of the second conductivity type, whichis located between substrate 12 of the first conductivity type andfloating body region 24 of the first conductivity type and which extendsbeneath insulating layers 26. Thus, and when multiple memory cells 3 arejoined in an array 81 to form a memory device 10 as schematicallyillustrated in FIG. 29, a buried layer 23 of a first memory cell 3, suchas memory cell “3 aa,” may be in electrical communication with a buriedlayer 23 of a second and/or an adjacent memory cell 3, such as memorycell “3 ab.”

Buried layer 23 may be formed in any suitable manner and/or using anysuitable process, illustrative, non-exclusive examples of which includeion implantation and/or epitaxial growth. Memory cell 3 also includesburied layer terminal 75 in addition to the terminals that are discussedin more detail herein with reference to memory cell 1.

FIGS. 30 and 31 provide illustrative, non-exclusive examples of anequivalent circuit representation of memory cell 3. As shown in FIG. 30,memory cell 3 includes n-p-n bipolar devices 330, 331, 332. Bipolardevice 330 is formed by buried layer 23, floating body 24, and BL1region 18. Bipolar device 331 is formed by buried layer 23, floatingbody 24, and SL region 16. Bipolar device 332 is formed by buried layer23, floating body 24, and BL2 region 20. Bipolar devices 330, 331, and332 are connected in parallel with a common buried well region 23 andfloating body region 24.

In FIG. 31, it can also be seen that memory cell 3 consists of twoadditional bipolar devices 333 (formed by BL1 region 18, floating bodyregion 24, and SL region 16) and 334 (formed by BL2 region 20, floatingbody region 24, and SL region 16) connected in series, where the SLregion 16 and the floating body 24 is shared between the two bipolardevices. In addition, memory cell 2 also consists of two field effecttransistors 335 (formed by BL1 region 18, gate 60 connected to WL1terminal 70, and SL region 16) and 336 (formed by BL2 region 20, gate 64connected to WL2 terminal 76, and SL region 16) connected in series,where the SL region 16 and the floating body 24 is shared between thetwo field effect transistors.

Memory cells 3 of FIG. 28 and/or array 81 of FIG. 29 may be operated ina plurality of states and/or modes and/or may be subject to a pluralityof operating conditions, or operations, which may include a plurality ofbiasing conditions for memory cells 3. The operation of memory cells 3and/or the response of memory cells 3 to various biasing conditions aresubstantially similar to the operation of memory cells 2 and/or theresponse of memory cells 2 to similar biasing conditions. However, inthe case of memory cells 3, the bias that was applied to substrateterminal 78 of memory cells 2 is applied to buried well terminal 75 ofmemory cells 3 and substrate terminal 78 of memory cells 3 is grounded.This reverse biases the p-n junction between substrate 12 and buriedwell layer 23, thereby decreasing a potential for leakage currentbetween substrate 12 and buried well layer 23.

Thus, the biasing conditions that are discussed in more detail hereinwith respect to memory cells 2 and FIGS. 16-19 will produce asubstantially similar response when applied to memory cells 3 and/orarray 81 of FIGS. 28 and 29 with the exception that the bias listed asbeing applied to substrate terminal 78 of memory cell 2 will be appliedto buried well terminal 75 of memory cell 3 and substrate terminal 78 ofmemory cell 3 will be grounded and/or have a 0.0 V bias applied thereto.Similarly, the circuitry that is discussed in more detail herein withreference to FIGS. 20 and 21 for memory cells 2 may be utilized toperform the holding operation on memory cells 3 with the exception thatthe back bias voltage may be applied to buried well terminal(s) 75instead of substrate terminal(s) 78. In addition, the response of memorycells 3 to various buried well potentials, or potentials that may beapplied to buried well terminal(s) 75, will be substantially similar tothe response of memory cells 2 to various substrate potentials, orpotentials that may be applied to substrate terminal(s) 78, as discussedin more detail herein with reference to FIGS. 22-23.

An alternative holding operation may be performed on memory cell 3, asdescribed in US 2010/0034041, “Method of Operating Semiconductor MemoryDevice with Floating Body Transistor Using Silicon Controlled RectifierPrinciple”, which is incorporated by reference herein in its entirety.The holding operation may be performed by applying the following biasconditions: zero voltage is applied to WL1 terminal 70 and/or WL2terminal 76, SL terminal 72, BL1 terminal 74 and/or BL2 terminal 77, apositive voltage is applied to the substrate terminal 78, while the BWterminal 76 is floating. Under these conditions, if memory cell 3 is inmemory/data state “1” with positive voltage in floating body 24, theintrinsic silicon controlled rectifier (SCR) device of memory cell 3,formed by the substrate 12, the buried well region 22, the floating bodyregion 24, and the regions 16 or 18 or 20, is turned on, therebymaintaining the state “1” data. Memory cells in state “0” will remain inblocking mode, since the voltage in floating body 24 is notsubstantially positive and therefore floating body 24 does not turn onthe SCR device. Accordingly, current does not flow through the SCRdevice and these cells maintain the state “0” data.

In this way, an array of memory cells 3 may be refreshed by periodicallyapplying a positive voltage pulse through substrate terminal 78. Thosememory cells 3 that are commonly connected to substrate terminal 78 andwhich have a positive voltage in body region 24 will be refreshed with a“1” data state, while those memory cells 3 that are commonly connectedto the substrate terminal 78 and which do not have a positive voltage inbody region 24 will remain in blocking mode, since their SCR device willnot be turned on, and therefore memory state “0” will be maintained inthose cells.

In one particular non-limiting embodiment, a voltage of about 0.0 voltsis applied to BL1 terminal 74 and/or BL2 terminal 77, a voltage of about0.0 volts is applied to WL1 terminal 70 and/or WL2 terminal 76, about0.0 volts is applied to SL terminal 72, and about +1.2 volts is appliedto terminal 78, while the BW terminal 76 is left floating. However,these voltage levels may vary, while maintaining the relativerelationships therebetween.

FIGS. 32-33 provide three-dimensional schematic representations ofadditional illustrative, non-exclusive examples of memory cells 3according to the present disclosure, while FIG. 34 is a top view of thememory cell of FIG. 32. Memory cells 3 of FIGS. 32-34 are substantiallysimilar to memory cells 1 of FIGS. 8-10 with the exception that memorycells 3 include well layer 23 instead of buried insulator layer 22between substrate 12 and fin 51 and/or floating body region 24. Inaddition, and as discussed in more detail herein, memory cells 3 alsoinclude buried well terminal 75 that is in electrical communication withwell layer 23 and further include insulating layers 26 between adjacentmemory cells 3, as shown in FIG. 34.

Similar to memory cells 1 and 2, and as discussed in more detail hereinwith reference to FIGS. 11 and 27, memory cells 3 may include anysuitable number of ports. An illustrative, non-exclusive example of amulti-port memory cell 3, in the form of a quad-port memory cell 3, isshown in FIG. 35. Multi-port memory cell 3 is substantially similar tomulti-port memory cell 1 of FIG. 11 with the exception that multi-portmemory cell 3 includes buried well layer 123 between substrate 108 andfloating body region 124 instead of buried insulator layer 122. Inaddition, buried well terminal 190 may be in electrical communicationwith buried well layer 123 and insulator layers 126 may separateadjacent memory cells 3.

FIG. 36 provides a schematic representation of an illustrative,non-exclusive example of a fourth embodiment 4 of a memory cell 9according to the present disclosure. The embodiment of FIG. 36 may bereferred to herein as dual-port memory cell 4, memory cell 4, and/orcell 4. Memory cell 4 is substantially similar to memory cell 3 of FIGS.28-35 with the exception that insulating layers 26, or trench isolationlayers 26, extend through buried layer 23 and into substrate 12, whileinsulating layers 28, or trench isolation layers 28 (shown in FIGS.38-40), end in buried well layer 23. Thus, and when memory cells 4 arejoined in an array 81 to form a memory device 10 as schematicallyillustrated in FIG. 37, a buried layer 23 of a first memory cell 4 (suchas memory cell “4 aa”) may not be in electrical communication with aburied layer 23 of a second and/or adjacent memory cell 4 (such asmemory cell “4 ba”) in one dimension of array 81 (such as columns 79).However, buried layer 23 of the first memory cell 4 (such has memorycell “4 aa”) may be in electrical communication with a buried layer 23of a third and/or adjacent memory cell 4 (such as memory cell “4 ab”)that is in a second dimension of array 81.

FIG. 38 is an illustrative, non-exclusive example of a two-dimensionallayout of array 81 of memory cells 4 when viewed from the top. Asdiscussed in more detail herein, the structure of cell 4 issubstantially similar to that of cell 3 with the exception of the depthof the trench isolation 26 that is isolating region 18 of one cell 4from region 20 of the adjacent cell 4 in array 81. Trench isolation 28in cell 3 ends in buried well layer 23, while the trench isolation 26 incell 4 breaks buried well layer 23 and ends in substrate 12.

FIG. 39 shows another embodiment of the two-dimensional layout of array81 of memory cells 4 when viewed from the top. The active regions 16,18, 20 and floating body 24 are formed at an angle other than 90 degreesto the word lines gates 60 and 66 to provide for easier vertical metalconnection routing of BL1, BL2 and SL terminals to regions 18, 20, and16, respectively. FIG. 39 shows a particular non-limiting example of a30 degree angle between gates 60 and 66 and the device area formed byregions 18, 16, and 20 and floating body 24. However, the angle may varywithout departing from the scope of the present disclosure.

The schematic view of memory cell 4 shown in FIG. 36 is an orthogonalcross section along lines I-I′ of FIG. 38, while FIG. 40 show anorthogonal cross section of cell 4 along lines II-II′ of FIG. 38. Theschematic cross-sections of FIGS. 36 and 40 illustrate that, asdiscussed in more detail herein, isolation layers 26 may break, and thusisolate, buried well layer 23 in one dimension, or direction, whileisolation layers 28 may not break, and thus may not isolate, buried welllayer 23 in another dimension, or direction. Thus, buried well terminal75 may be shared across the entire row/column. Buried well terminal 75from each row/column may be connected together across the entire array81 for mass parallel holding operation and/or also may be segmented toprovide for independent control of the applied bias on a selectedportion of array 81 of memory cells 4. The memory operations (holding,row-wide write ‘0’, bit-selective write ‘0’ and write ‘1’) of memorycell 4 and/or array 81 of FIGS. 36-40 are identical to those of memorycell 3 and/or array 81 of FIGS. 28-35 and are discussed in more detailherein with reference thereto. The alternate holding operation employingsilicon rectifier principle as described for example in US 2010/0034041,“Method of Operating Semiconductor Memory Device with Floating BodyTransistor Using Silicon Controlled Rectifier Principle”, which isincorporated by reference herein in its entirety, may also be employedto memory cell 4.

FIGS. 41-42 provide three-dimensional schematic representations ofadditional illustrative, non-exclusive examples of memory cells 4according to the present disclosure, while FIG. 43 is a top view of thememory cell of FIG. 41. In FIGS. 41-43, insulating layers 28 areorthogonal to insulating layers 26. Memory cells 4 of FIGS. 41-43 aresubstantially similar to memory cells 3 of FIGS. 32-34 with theexception that, as discussed in more detail herein, trench isolation 26in cell 4 ends in substrate 12. Similar to memory cell 3, the orthogonaltrench isolation 28 in cell 4 is shallower and ends in the buried welllayer 23.

FIG. 44 provides a schematic representation of an illustrative,non-exclusive example of a transistor 500 according to the presentdisclosure that may be included in and/or form a portion of memory cells9. Transistor 500 includes a substrate 12 of a first conductivity type,such as a p-type conductivity type, for example. Substrate 12 mayinclude any suitable substrate formed from any suitable material,illustrative, non-exclusive examples of which are discussed in moredetail herein. Substrate 12 has a surface 14. A first region 18 having asecond conductivity type, such as an n-type conductivity type, isprovided in substrate 12 and is exposed at surface 14. A second region20 having the second conductivity type is also provided in substrate 12,which is exposed at surface 14 and which is spaced apart from the firstregion 18. First and second regions 18 and 20 may be formed using anysuitable method and/or process, illustrative, non-exclusive examples ofwhich include ion implantation and/or solid state diffusion, and arediscussed in more detail herein.

A buried layer 23 of the second conductivity type is also provided inthe substrate 12, as shown. A floating body region 24 having the firstconductivity type, such as a p-type conductivity type, is bounded bysurface, first and second regions 18, 20, insulating layers 26 and 28,and buried layer 23. Buried layer 23 and/or floating body region 24 maybe formed using any suitable process and/or method, illustrative,non-exclusive examples of which include ion implantation and/orepitaxial growth and are discussed in more detail herein.

Insulating layers 26 and 28 (e.g. shallow trench isolation (STI)) may beformed from any suitable dielectric material, illustrative,non-exclusive examples of which are discussed in more detail herein.Insulating layers 26 insulate region 18 of transistor 500 from region 18of neighboring transistor 500 and insulate buried well 23 of transistor500 from buried well 23 of neighboring transistor 500 when multipletransistors 500 are joined to form a memory device and/or array oftransistors 500. Insulating layers 28 insulate regions 18, 20, andfloating body 24 of cell 500 from regions 18, 20, and floating body 24of neighboring transistor 500 when multiple transistors 500 are joinedto form the memory device and/or array of transistors 500.

Similar to memory cells 4, and as discussed in more detail herein withreference to FIGS. 36-40, insulating layers 28 may be orthogonal toinsulating layers 26. Trench isolation 26 in transistor 500 ends insubstrate 12. The orthogonal trench isolation 28 in transistor 500 isshallower and ends in the buried well layer 23. A gate 60 is positionedin between the regions 20 and 18, and above the surface 14. The gate 60is insulated from surface 14 by an insulating layer 62. A gate 61 ispositioned in between the regions 20 and insulating layer 26, and abovethe surface 14. The gate 61 is insulated from surface 14 by aninsulating layer 63. Insulating layers 62 and 63 may be formed from anysuitable dielectric material, illustrative, non-exclusive examples ofwhich are discussed in more detail herein. Similarly, gates 60 and 61may be formed from any suitable conductive material, illustrative,non-exclusive examples of which are discussed in more detail herein.

Transistor 500 further includes terminal 70 electrically connected togates 60 and 61, terminal 68 electrically connected to region 18,terminal 69 electrically connected to region 20, buried layer terminal75 electrically connected to buried well (BW) 23, and substrate terminal78 electrically connected to substrate 12.

FIG. 45 provides a schematic representation of an illustrative,non-exclusive example of a fifth embodiment 5 of a memory cell 9according to the present disclosure that includes transistor 500. Theembodiment of FIG. 45 may be referred to herein as memory cell 5 and/orcell 5.

Memory cell 5 of FIG. 45 includes transistor 500 and pass transistors528 and 529, which also may be referred to herein as access transistors528 and 529. Pass transistors 528 and 529, which also may be referred toherein as a first transistor 528 and a second transistor 529, mayinclude regular field-effect transistors, such as n-type metal oxidesemiconductor field-effect transistors (MOSFET). The source terminal oftransistor 528 is connected to terminal 68 of transistor 500 and thesource terminal of transistor 529 is connected to terminal 69 oftransistor 500. Cell 5 consists of bit line #1 (BL1) terminal 74electrically connected to a drain terminal of first transistor 528, wordline #1 (WL1) terminal 72 electrically connected to a gate terminal offirst transistor 528, gate assist (GA) terminal 70 electricallyconnected to gate 60 and gate 61 of transistor 500, word line #2 (WL2)terminal 76 electrically connected to a gate terminal of secondtransistor 529, bit line #2 (BL2) terminal 77 electrically connected toa drain terminal of second transistor 529, buried well (BW) terminal 75electrically connected to buried layer 22, and substrate terminal 78electrically connected to substrate 12. WL1 terminal 72 and BL1 terminal74 may be referred to herein as ‘port #1’ and WL2 terminal 76 and BL2terminal 77 may be referred to herein as ‘port #2’.

FIG. 46 shows a simplified equivalent circuit of cell 5. Multiple memorycells 5 may be joined in an array 81 to form a portion of a memorydevice 10 as shown in FIGS. 47-48. Array 81 shown in FIG. 47 isconfigured with the gate assist (GA) terminals 70 parallel to the bitline (BL) terminals 74 and 77 (i.e., in the column 79 direction), whilethe array 81 shown in FIG. 18 is configured with the gate assist (GA)terminals 70 parallel to the word line (WL) terminals 72 and 76 (i.e.,in the row 80 direction). In another embodiment, the transistor 500 hasan n-type conductivity type as the first conductivity type and p-typeconductivity type as the second conductivity type, as noted above, andpass transistors 528 and 529 are p-type MOSFETs.

FIG. 49 provides an illustrative, non-exclusive example of an equivalentcircuit representation of memory cell 5. Memory cell 5 includes passtransistors 528 and 529, which also may be referred to herein asfield-effect transistors 528 and 529. In addition, memory cell 5 alsoincludes field-effect transistors 530, formed by region 18, floatingbody 24, gate 60 and region 20, n-p-n bipolar devices 531, 532 formed byburied layer 23, floating body 24, regions 18 and 20 and diode 533formed by substrate 12 and buried layer 23. The p-type substrate 12 ofthe current embodiment of the memory cell 5 will be grounded, reversebiasing the p-n junction between substrate 12 and buried well layer 23,thereby decreasing a potential for leakage current between substrate 12and buried well layer 23.

The operation of memory cell 5 is largely determined by theemitter-collector (regions 18/20 and buried well 23) voltage potentialof bipolar devices 531, 532 and their operation is the same regardlessof the polarity of the applied voltage potential. Hence, the operationof memory cell 5 may be controlled by either active-low bit lines(terminals 74/77) or active-high bit lines. Active-low operation refersto applying a zero voltage level for activating a bit line whilemaintaining a positive voltage level for unselected bit lines.Active-high operation refers to applying a positive voltage level foractivating a bit line while maintaining a zero voltage level forunselected bit lines.

Illustrative, non-exclusive examples of operations for memory cells 5according to the present disclosure include an idle state and/oroperation, a holding/refresh via port #1 operation, a holding/refreshvia port #2 operation, a holding/refresh via port #1 and port #2operation, a read port #1 only operation, a read port #2 only operation,a simultaneous read port #1 and port #2 operation, a row-wide write ‘0’operation, a bit-selective write ‘0’ port #1 operation, a bit-selectivewrite ‘0’ port #2 operation, a write ‘1’ port #1 with gate assistoperation, a write ‘1’ port #2 with gate assist operation, a compactwrite ‘1’ port #1 operation, and/or a compact write ‘1’ port #2operation. FIG. 50 provides illustrative, non-exclusive examples ofbiasing conditions that may be utilized to perform the idle,holding/refresh via port #1, holding/refresh via port #2, and/orholding/refresh via port #1 and port #2 operations when memory cell 5 isoperated in the active-high operation. FIG. 51 provides illustrative,non-exclusive examples of biasing conditions that may be utilized toperform the read port #1 only, read port #2 only, and/or simultaneousread ports #1 and #2 operations when memory cell 5 is operated in theactive-high state. In addition, FIG. 52 provides illustrative,non-exclusive examples of biasing conditions that may be utilized toperform the row-wide write ‘0’, bit-selective write ‘0’ port #1, and/orbit-selective write ‘0’ port #2 operations when memory cell 5 isoperated in the active-high state. FIG. 53 provides illustrative,non-exclusive examples of biasing conditions that may be utilized toperform the write ‘1’ port #1 with gate assist, write ‘1’ port #2 withgate assist, compact write ‘1’ port #1, and/or compact write ‘1’ port #2operations when memory cell 5 is operated in the active-high state.

Similarly, FIG. 54 provides illustrative, non-exclusive examples ofbiasing conditions that may be utilized to perform the idle,holding/refresh via port #1, holding/refresh via port #2, and/orholding/refresh via port #1 and port #2 operations when memory cell 5 isoperated in the active-low operation. FIG. 55 provides illustrative,non-exclusive examples of biasing conditions that may be utilized toperform the read port #1 only, read port #2 only, and/or simultaneousread ports #1 and #2 operations when memory cell 5 is operated in theactive-low state. In addition, FIG. 56 provides illustrative,non-exclusive examples of biasing conditions that may be utilized toperform the row-wide write ‘0’, bit-selective write ‘0’ port #1, and/orbit-selective write ‘0’ port #2 when memory cell 5 is operated in theactive-low state, while FIG. 57 provides illustrative, non-exclusiveexamples of biasing conditions that may be utilized to perform the write‘1’ port #1 with gat assist, write ‘1’ port #2 with gate assist, compactwrite ‘1’ port #1, and/or compact write ‘1’ port #2 operations whenmemory cell 5 is operated in the active-low state.

With reference to FIG. 45 for a single memory cell 5 and FIG. 47 for anarray 81 of memory cells 5, FIG. 50 provides illustrative, non-exclusiveexamples of biasing conditions that may be utilized when array 81 is inthe idle state, with memory cells 5 is operated in the active-highstate. Memory cells 5 will be in idle mode when gates of both passtransistors 528 and 529 are turned off. The negative voltage applied tothe word lines WL1 terminal 72 and WL2 terminal 76 may decrease apotential for column disturb during the bit-selective write ‘0’operation that will be described below. In the idle mode, a positivecharge that may be stored in floating body region 24 will decrease overtime due to p-n diode leakage formed by floating body 24 and regions 16,18, and buried layer region 23 and due to charge recombination, and aperiodic holding operation may be utilized to maintain the positivecharge stored in the floating body 24 as described below.

FIG. 50 further provides illustrative, non-exclusive examples of biasingconditions that may be utilized to perform the holding operation viaport #1, port #2, and/or via port #1 and port #2 simultaneously, withmemory cells 5 operated in the active-high state. By applying a positivevoltage bias to the word line terminal(s), transistor 528/529 will turnon and provide a voltage potential difference between bit line terminals74 and/or 77 and BW terminal 75, which are the emitter and collectorterminals of bipolar transistors 531/532.

If floating body 24 is positively charged (i.e. in a state ‘1’), thebipolar transistors 531 and 532 will be turned on. A fraction of thebipolar transistor current will then flow into floating body region 24(usually referred to as the base current) and maintain the state ‘1’data. The efficiency of the holding operation can be enhanced bydesigning the bipolar devices 531, 532 formed by buried well 23,floating body region 24, and regions 18/20 to be a low-gain bipolardevice, where the bipolar gain is defined as the ratio of the collectorcurrent flowing out of buried well terminal 75 to the base currentflowing into the floating body region 24.

For memory cells in state ‘0’ data, the bipolar devices 531, 532 willnot be turned on, and consequently no base hole current will flow intofloating body region 24. Therefore, memory cells in state ‘0’ willremain in state ‘0’.

The state of the memory cell 5 may be maintained by refreshing thecharge stored in floating body 24. This holding operation may beperformed by applying a periodic positive voltage pulse to the back biasterminal (i.e., BW terminal 75). The refresh cycle may be performed as amass parallel operation by turning on multiple word line rows and/or bitline columns of array 81, during which a read or write operation must besuspended. FIG. 58 illustrates multiplexers 46 that may determine thebias applied to the word line and/or bit line terminals, where thecontrol signal 42 may be the output of a refresh circuitry 44. Onerefresh circuitry may control a single, multiple or all word lines andbit lines in array 81. Multiplexers 46 choose whether the word lines andbit lines receive individual voltage biases from Address Decoder VoltageGenerator 40 depending on different operating modes as described lateror refresh voltage biases as described above.

The charge stored in floating body 24 may be sensed by monitoring thecell current of the memory cell 5. If cell 5 is in a state ‘1’ havingholes in the floating body region 24, then the bipolar junctiontransistors 531 and 532 will be turned on and current will flow out ofterminals 68 and 69 if there is voltage potential difference betweenterminals 68 and 69 and buried well 23. If cell 5 is in a state ‘0’having no holes in the floating body region 24, then the bipolarjunction transistors 531 and 532 will be turned off and no current willflow out of terminals 68 and 69. A sensing circuit/read circuitry 90typically connected to BL1 terminal 74 and/or BL2 terminal 77 of memoryarray 81 (e.g., see read circuitry 90 in FIG. 59) may then be used todetermine the data state of the memory cell. As shown in FIG. 7,reference generator circuitry 92 may also be used during the operationof read circuitry 90.

A read operation on memory cell 5 may be performed independently by port#1 and port #2 irrespective of timing. However, read and writeoperations cannot occur simultaneously in order to avoid readingincorrect data. See descriptions below for details on the writecontention avoidance.

FIG. 51 further provides illustrative, non-exclusive examples of biasingconditions that may be utilized to perform the read operation via port#1, port #2, and/or via port #1 and port #1 simultaneously, with memorycells 5 operated in the active-high state. As a result of the biasconditions applied as described, the unselected memory cells will be atidle mode, maintaining the states of the respective floating bodies 24thereof.

Writing ‘0’ to cell 5 may be done in a plurality of ways, including: 1)Row-wide write ‘0’, where an entire selected row in a memory array 81 iswritten with ‘0’s, and 2) Bit-selective write ‘0’, where the write ‘0’operation may be performed on a specific memory cell without affectingunselected cells in the array. Row-wide write ‘0’ is useful for memoryreset or erase for any particular row and/or group of rows in array 81and may be done via the back bias BW terminal that is common to bothports. Bit-selective write ‘0’ is useful for regular random memoryaddress write operations and may be done via either port #1 or port #2.

FIG. 52 provides illustrative, non-exclusive examples of biasingconditions that may be utilized to perform the row-wide write ‘0’operation and/or bit-selective write ‘0’ operation via port #1 and/orport #2, with memory cells 5 operated in the active-high operation. Whenmemory cell 5 and/or array 81 is biased for the row-wide write ‘0’operation, the p-n junctions (junction between 24 and 23) areforward-biased, evacuating any holes from the floating body 24 andwriting the ‘0’ data state to the selected memory cells 5. The biasconditions for all the unselected cells are the same since the write ‘0’operation only involves applying a negative voltage to the BW terminal75 (thus to the entire row or multiple connected rows). As may be seen,the unselected memory cells will be in idle operation.

Bit-selective write ‘0’ operation to cell 5 can only be done by eitherport #1 or port #2 at any given time but not by both simultaneously.Furthermore, during a write operation, the other port cannot perform aread operation and vice versa. A write operation has to be completedbefore a read operation by either port may commence or a read operationmust be completed before a write operation by either port can commence.See descriptions below for details on the write contention avoidance.

FIG. 52 further provides illustrative, non-exclusive examples of biasingconditions that may be utilized to perform the bit-selective write ‘0’on port #1 or port #2, with memory cells 5 operated in the active-highstate. When memory cell 5 and/or array 81 is biased for thebit-selective write ‘0’ operation, the p-n junction (junction between 24and 18) is forward-biased, evacuating any holes from the floating body24. The unselected cells 5 not sharing the same WL1 or BL1 terminal (forthe bit-selective write ‘0’ on port #1) or the same WL2 or BL2 terminal(for the bit-selective write ‘0’ on port #2) as the selected cell 5 willremain at idle state.

The write ‘1’ operation may be performed in a plurality of ways,including: 1) Write ‘1’ with gate assist and 2) compact write ‘1’ wheregate assist terminal is not used. As with the write ‘0’ operation, thewrite ‘1’ operation only may be performed by one of the ports at a giventime and during the write process, a read operation cannot be performed.

FIG. 53 provides illustrative, non-exclusive examples of biasingconditions that may be utilized to perform the write 1′ with gate assistoperation via band-to-band tunneling mechanism to cell 5 by port #1,with memory cells 5 operated in the active-high state. The negative biason GA terminal 70 and the positive bias on BL1 terminal 74 will resultin hole injection to the floating body 24, and the unselected cells 5will remain at the idle mode.

FIG. 53 also provides illustrative, non-exclusive examples of biasingconditions that may be utilized to perform the write ‘1’ with gateassist operation via band-to-band tunneling mechanism to cell 5 by port#2, with memory cells 5 operated in the active-high state. The negativebias on GA terminal 70 and the positive bias on BL2 terminal 77 willresult in hole injection to the floating body 24, and the unselectedcells 5 will remain at the idle mode.

For memory cells sharing the same row as the selected memory cell, boththe GA terminal 70 and BL1/BL2 terminals 74/77 are at about 0.0 volt.Comparing with the idle mode bias condition, it can be seen that cellssharing the same row (i.e. the same WL1/WL2 terminals 72/76) are in idlemode. As a result, the states of these memory cells will remainunchanged.

For memory cells sharing the same column as the selected memory cell, azero or negative voltage is applied to the WL1/WL2 terminals 72/76. As aresult, the transistors 528/529 connected to transistor 500 will beturned off and memory cell 5 is in idle mode as described above,maintaining the state of the floating body charge. For memory cells notsharing the same row or the same column as the selected memory cell, theWL1/WL2 terminals 72/76 will have a zero or negative applied voltage andGA terminal 70 will be at zero voltage, putting the memory cells at idlemode.

FIG. 53 further provides illustrative, non-exclusive examples of biasingconditions that may be utilized to perform the compact write ‘1’operation to cell 5 by port #1 via impact ionization mechanism, withmemory cells 5 operated in the active-high operation. The large positivebias on BL1 terminal 74 will result in net current flow into thefloating body 24, and the unselected cells 5 will remain at the idlemode.

FIG. 53 also provides illustrative, non-exclusive examples of biasingconditions that may be utilized to perform the compact write ‘1’operation to cell 5 by port #2 via impact ionization mechanism, withmemory cells 5 operated in the active-high operation. The large positivebias on BL2 terminal 77 will result in net current flow into thefloating body 24, and the unselected cells 5 will remain at the idlemode.

For memory cells sharing the same row as the selected memory cell, boththe BL terminals 74/77 are at 0.0 volt. Comparing with the idle modebias condition, it can be seen that cells sharing the same row (i.e. thesame WL1/WL2 terminals 72/76) are in idle mode. As a result, the statesof these memory cells will remain unchanged.

For memory cells sharing the same column as the selected memory cell, azero or negative voltage is applied to the WL1/WL2 terminals 72/76. As aresult, the transistors 528/529 connected to transistor 500 will beturned off and memory cell 5 is in idle mode as described above,maintaining the state of the floating body charge. For memory cells notsharing the same row or the same column as the selected memory cell, theWL1/WL2 terminals 72/76 have a zero or negative voltage applied and theBL1/BL2 terminals are at 0.0 volt, putting the memory cells at idlemode.

As discussed in more detail herein, the operation of memory cells 5 alsomay be controlled by active-low bit lines terminal 74/77. Generally, thepolarity between BL1 or BL2 terminals 74 or 77 and buried well terminal75 is reversed from the active-low bit lines operation, with theexception of when the bit lines are asserted a negative voltage. Thebiasing conditions that may be utilized to perform the above operationswhen memory cells 5 are operated in the active-low state are shown inFIGS. 54-57.

As discussed in more detail herein, FIG. 48 shows another embodiment ofarray 81, where the gate assist GA terminal 70 is laid out on a rowparallel to the word line terminals 72 and 76. All operations of memorycell 5 with row gate assist are identical to those with column gateassist as summarized in FIGS. 50-57 with the exception of write ‘1’operation with gate assist using active-low bit lines. Write ‘1’operation with gate assist using row GA terminal will write state ‘1’ tothe entire row since the word line WL1 or WL2 terminal 72 or 76 isactivated and the bit line BL1 or BL2 terminal 74 or 77 is at logic highfor the entire row. Consequently, active-low bit line write 1′ operationwith gate assist will result in a row-wide write ‘1’ operation.

FIG. 60 shows the biasing conditions for the row-wide write ‘1’ withgate assist operation for array 81 of FIG. 48. Active-high bit lineoperations of array 81 with row gate assist are identical to active-lowbit line operations of array 81 with column gate assist.

FIGS. 61-62 provide three-dimensional schematic representations ofadditional illustrative, non-exclusive examples of transistor 500according to the present disclosure, while FIG. 63 is a top view of thetransistor of FIG. 61. In this embodiment, transistor 500 has a finstructure 51 fabricated on substrate 12 having a first conductivity type(such as p-type conductivity type) so as to extend from the surface ofthe substrate to form a three-dimensional structure, with fin 51extending substantially perpendicularly to, and above the top surface ofthe substrate 12. Fin structure 51 includes first and second regions 18,20 having the second conductivity type. The floating body region 24 isbounded by the top surface of the fin 51, the first and second regions18, 20 and insulating layers 26 and 28 (insulating layers 26 and 28 canbe seen in the top view of FIG. 63).

Insulating layers 26 insulate region 18 and floating body 24 oftransistor 500 from floating body 24 of neighboring transistor 500 andinsulate buried well 23 of transistor 500 from buried well 23 ofneighboring transistor 500 when multiple transistors 500 are joined tomake a memory device (array 81). Insulating layers 28 insulate regions18, 20 and floating body 24 of transistor 500 from regions 18, 20 andfloating body 24 of neighboring transistor 500 when multiple transistors500 are joined to make a memory device (array 81), but not the buriedwell region 23. As discussed in more detail herein, insulating layers 28may be orthogonal to insulating layers 26.

Trench isolation 26 in transistor 500 ends in substrate 12. Theorthogonal trench isolation 28 in transistor 500 is shallower and endsin the buried well layer 23. The floating body region 24 is conductivehaving a first conductivity type (such as p-type conductivity type). Fin51 may be formed from any suitable material, illustrative, non-exclusiveexamples of which are discussed in more detail herein. A buried layer 23of the second conductivity type is also provided in the substrate 12,buried in the substrate 12, as shown.

Transistor 500 further includes gate 60 on two opposite sides of thefloating body region 24 as shown in FIG. 61. Alternatively, gate 60 mayenclose three sides of the floating substrate region 24 as shown in FIG.62. Gate 60 is insulated from floating body 24 by insulating layer 62.Gate 60 is positioned between the first and second regions 18, 20,adjacent to the floating body 24. Memory cells 9 including transistor500 with fin 51 may include several terminals: terminals 68 and 69, gateassist (GA) terminal 70, buried well (BW) terminal 75 and substrateterminal 78.

FIG. 64 provides a schematic representation of an illustrative,non-exclusive example of a transistor 600 according to the presentdisclosure that may be included in and/or form a portion of memory cells9. Transistor 600 includes a substrate 12 of a first conductivity type,such as a p-type conductivity type, for example. The substrate 12 has asurface 14. A first region 18 having a second conductivity type, such asan n-type conductivity type, is provided in substrate 12 and is exposedat surface 14. A second region 20 having the second conductivity type isalso provided in substrate 12, which is exposed at surface 14 and whichis spaced apart from the first region 18. First and second regions 18and 20 may be formed using any suitable process and/or method,illustrative, non-exclusive examples of which include ion implantationand/or solid state diffusion.

A buried layer 23 of the second conductivity type is also provided inthe substrate 12, buried in the substrate 12, as shown. A floating bodyregion 24 having a first conductivity type, such as a p-typeconductivity type, is bounded by surface 14, first and second regions18, 20, insulating layers 26 and 28, and buried layer 23.

Insulating layers 26 insulate region 18 of transistor 600 from region 20of neighboring transistor 600 and insulate buried well 23 of transistor600 from buried well 23 of neighboring transistor 600 when multipletransistors 600 are joined to form a memory device (such as in an arrayof transistors 600). Insulating layers 28 (shown in FIG. 81) insulateregions 18, 20, and floating body 24 (but not the buried well 23) oftransistor 600 from regions 18, 20, and floating body 24 of neighboringtransistor 600 when multiple transistors 600 are joined to form thememory device. Insulating layers 28 may be orthogonal to insulatinglayers 26. The trench isolation 26 in transistor 600 ends in substrate12. The orthogonal trench isolation 28 in transistor 600 is shallowerand ends in the buried well layer 23.

A gate 60 is positioned in between the regions 20 and 18, and above thesurface 14. The gate 60 is insulated from surface 14 by an insulatinglayer 62.

Transistor 600 further includes terminal 70 electrically connected togate 60, terminal 68 electrically connected to region 18, terminal 69electrically connected to region 20, buried layer terminal 75electrically connected to buried well (BW) 23, and substrate terminal 78electrically connected to substrate 12.

FIG. 65 provides a schematic representation of an illustrative,non-exclusive example of a sixth embodiment 6 of a memory cell 9according to the present disclosure that includes transistor 600. Theembodiment of FIG. 61 may be referred to herein as memory cell 6 and/orcell 6.

Memory cell 6 of FIG. 65 includes pass transistors 628 and 629, whichalso may be referred to herein as access transistors 628 and 629 and maybe substantially similar to pass transistors 528 and 529 of FIG. 45. Thesource terminal of transistor 628 is connected to terminal 68 oftransistor 600 and the source terminal of transistor 629 is connected toterminal 69 of transistor 600. Cell 6 consists of bit line #1 (BL1)terminal 74 electrically connected to drain terminal of first transistor628, word line #1 (WL1) terminal 72 electrically connected to gateterminal of first transistor 628, gate assist (GA) terminal 70electrically connected to gate 60 of transistor 600, word line #2 (WL2)terminal 76 electrically connected to gate terminal of transistor 629,bit line #2 (BL2) terminal 77 electrically connected to drain terminalof transistor 629, buried well (BW) terminal 75 electrically connectedto buried layer 23, and substrate terminal 78 electrically connected tosubstrate 12. WL1 terminal 72 and BL1 terminal 74 may be referred toherein as ‘port #1’ and WL2 terminal 76 and BL2 terminal 77 may bereferred to herein as ‘port #2’.

FIG. 66 shows a simplified circuit diagram of cell 6. Multiple memorycells 6 may be joined in an array 81 to make a memory device 10, or aportion thereof, as shown in FIGS. 67 and 68. In another embodiment,transistor 600 has an n-type conductivity type as the first conductivitytype and p-type conductivity type as the second conductivity type, asnoted above, and the transistors 628 and 629 are p-type MOSFETs.

FIG. 69 provides an illustrative, non-exclusive example of an equivalentcircuit representation of memory cell 6. Memory cell 6 includes passtransistors 628 and 629, which also may be referred to herein asfield-effect transistors 628 and 629. In addition, memory cell 6 alsoincludes field-effect transistors 630, formed by region 18, floatingbody 24, gate 60 and region 20, n-p-n bipolar devices 631, 632 formed byburied layer 23, floating body 24, regions 18 and 20 and diode 633formed by substrate 12 and buried layer 23. The p-type substrate 12 ofthe current embodiment of the memory cell 6 will be grounded, reversebiasing the p-n junction between substrate 12 and buried well layer 23,thereby preventing any leakage current between substrate 12 and buriedwell layer 23.

The operations for memory cells 6 are substantially similar to theoperations for memory cells 5 of FIGS. 49-59 and include operations withactive-low and active-high bit lines. With reference to FIG. 65 for asingle memory cell 6 and FIG. 67 for an array 81 of memory cells 6,illustrative, non-exclusive examples of operations and/or biasingconditions for memory cells 6 according to the present disclosure areshown in FIGS. 70-77.

FIG. 70 provides illustrative, non-exclusive examples of biasingconditions that may be utilized to perform the various idle and/orholding/refresh operations on memory cells 5, while FIG. 71 providesillustrative, non-exclusive examples of biasing conditions that may beutilized to perform the various read operations on memory cells 6 whenmemory cells 6 are operated in the active-high operation. FIG. 72provides illustrative, non-exclusive examples of biasing conditions thatmay be utilized to perform the various write ‘0’ operations on memorycells 6, while FIG. 73 provides illustrative, non-exclusive examples ofbiasing conditions that may be utilized to perform the various write 1′operations on memory cells 6 when memory cells 6 are operated in theactive-high state.

Similarly, FIG. 74 provides illustrative, non-exclusive examples ofbiasing conditions that may be utilized to perform the various idleand/or holding/refresh operations on memory cells 6, while FIG. 75provides illustrative, non-exclusive examples of biasing conditions thatmay be utilized to perform the various read operations on memory cells 6when memory cells 6 are operated in the active-low operation. FIG. 76provides illustrative, non-exclusive examples of biasing conditions thatmay be utilized to perform the various write ‘0’ operations on memorycells 6, while FIG. 77 provides illustrative, non-exclusive examples ofbiasing conditions that may be utilized to perform the various write ‘1’operations on memory cells 6 when memory cells 6 are operated in theactive-low operation.

As discussed in more detail herein, FIG. 68 shows another embodiment ofarray 81 of memory cells 6, where the gate assist GA terminal 70 is laidout in a row parallel to the word line terminals 72 and 76. Similar tomemory cells 5, all operations of memory cell 6 with row gate assist areidentical to those with column gate assist as summarized in FIGS. 70-77with the exception of write ‘1’ operation with gate assist usingactive-low bit lines. The write ‘1’ operation with gate assist usingactive-low bit lines will write state ‘1’ to the entire row since theword line WL1 or WL2 terminal 72 or 76 is activated and the bit line BL1or BL2 terminal 74 or 77 is at logic high for the entire row.Consequently, active-low bit line write 1′ operation with gate assistwill result in a row-wide write ‘1’ operation.

FIG. 78 shows the biasing conditions for the row-wide write ‘1’ withgate assist operation for array 81 of FIG. 68. Active-high bit lineoperations of array 81 with row gate assist are identical to active-lowbit line operations of array 81 with column gate assist.

FIGS. 79-80 provide three-dimensional schematic representations ofadditional illustrative, non-exclusive examples of transistor 600according to the present disclosure, while FIG. 81 is a top view of thetransistor of FIG. 79. In this embodiment, transistor 600 has a finstructure 51 fabricated on substrate 12 having a first conductivity type(such as p-type conductivity type) so as to extend from the surface ofthe substrate to form a three-dimensional structure, with fin 51extending substantially perpendicularly to, and above the top surface ofthe substrate 12. Fin structure 51 includes first and second regions 18,20 having the second conductivity type. The floating body region 24 isbounded by the top surface of the fin 51, the first and second regions18, 20 and insulating layers 26 and 28 (insulating layers 26 and 28 canbe seen in the top view of FIG. 81).

Insulating layers 26 insulate region 18 and floating body 24 oftransistor 600 from region 20 and floating body 24 of neighboringtransistor 600 and insulate buried well 23 of transistor 600 from buriedwell 23 of neighboring transistor 600 when multiple transistors 600 arejoined to make a memory device (array 81). Insulating layers 28 insulateregions 18, 20 and floating body 24 of transistor 600 from regions 18,20 and floating body 24 of neighboring transistor 600 when multipletransistors 600 are joined to make a memory device (array 81).Insulating layers 28 may be orthogonal to insulating layers 26. Thetrench isolation 26 in transistor 600 ends in substrate 12.

The orthogonal trench isolation 28 in transistor 600 is shallower andends in the buried well layer 23. A buried layer 23 of the secondconductivity type is also provided in substrate 12, as shown. Transistor600 further includes gate 60 on two opposite sides of the floatingsubstrate region 24 as shown in FIG. 79. Alternatively, gate 60 mayenclose three sides of the floating substrate region 24 as shown in FIG.80. Gate 60 is insulated from floating body 24 by insulating layer 62.Gate 60 is positioned between the first and second regions 18, 20,adjacent to the floating body 24. Memory cells 9 including transistor600 with fin 51 may include several terminals: terminals 68 and 69, gateassist (GA) terminal 70, buried well (BW) terminal 75 and substrateterminal 78.

FIG. 82 shows an embodiment of a true dual-port memory using memoryarrays 81 described above with its control circuitry, where port #1 andport #2 have independent access to the memory array as described above.The memory array block in FIG. 82 may include any of the above describedarrays 81 including memory cells 1, 2, 3, 4, 5, and/or 6 of the presentdisclosure. The Read/Write Control (R/W Control 58) circuitry isresponsible for conflict resolution when either port #1 or port #2 is orboth port #1 and port #2 are performing write operation to the samememory cell 1, 2, 3, 4, 5, and/or 6 in array 81.

Control 58 regulates the following conflict resolutions: read beforewrite, write before read, write port #1 before write port #2, and writeport #2 before write port #1 based on the MODE input signaling. ‘Readbefore write’ represents the condition where the read operation by oneof port #1 or port #2 takes precedence and must be completed before awrite operation from the other port can commence on the same memory cellin the same clock cycle. ‘Write before read’ represents the conditionwhere the write operation by one of port #1 or port #2 takes precedenceand must be completed before a read operation from the other port cancommence on the same memory cell in the same clock cycle. ‘Write port #1before write port #2’ represents the condition where write operation byport #1 takes precedence and must be completed before write operation byport #2 can commence on the same memory cell in the same clock cycle.‘Write port #2 before write port #1’ represents the condition wherewrite operation by port #2 takes precedence and must be completed beforewrite operation by port #1 can commence on the same memory cell in thesame clock cycle.

Read operation is performed by asserting the address lines on port #1and/or port #2 through Address Registers 50 a/50 b. The AddressRow/Column Decoder 55 a/55 b decodes the Address Registers 50 a/50 boutputs and selects the intended memory cell by providing the propervoltage biases as described above. The resulting bit line current issensed by the Read Sense Amp 57 a/57 b, which is then driven to ReadData Output Registers 54 a/54 b.

Write operation is performed by asserting the address lines on port #1and/or port #2 to the Address Registers 50 a/50 b and the data lines onport #1 and/or port #2 to the Data Input Registers 52 a/52 b. TheAddress Row/Column Decoder 55 a/55 b decodes the Address Registers 50a/50 b outputs and selects the intended memory cell by providing theproper voltage biases as described above. When Write Enable signal (WE)is asserted, data from the Data Input Registers 52 a/52 b are latchedinto the memory array through the Write Driver 56 a/56 b.

Alternatively, FIG. 83 shows another embodiment of a dual-port memorycircuitry, where only one of port #1 or port #2 has read and writeoperation ability and the other port only has read operation ability.FIG. 83 shows an example where port #1 has full read and write controlcircuitry as described above and port #2 has the read data outputcircuitry but not the write data input circuitry. Read, write andconflict resolution operations are the same as described above with theexception of the ‘write port #1 before write port #2’ and ‘write port #2before write port #1’ modes, where they become unnecessary.

FIG. 84 shows an embodiment of a First-In-First-Out (FIFO) memorycircuitry using the memory arrays 81 described above with port #1serving as write port and port #2 operating as read port. The memoryarray block in FIG. 81 may be any array 81. Similar asynchronous FIFOcircuits were described in “Asynchronous FIFO Circuit and Method ofReading and Writing Data Through Asynchronous FIFO Circuit” U.S. Pat.No. 6,810,468 B2 by Miyamoto et al. In our present disclosure, thememory array uses the dual port memory array 81 as discussed in moredetail herein.

The write operation to the FIFO circuit is initiated by asserting the WRsignal to the Write Pointer circuit 94 along with its write data valueto the Write Pointer Decoder circuit 95 into port #1 of array 81. TheWrite Pointer circuit 94 includes a counter that increments the memoryaddress location within array 81 for each write operation performed.Write Pointer Decoder circuit 95 determines the memory cell location towrite to within the array 81 and provides the proper write voltagebiases to memory cell 1, 2, 3, 4, 5, and/or 6 terminals as describedabove. The read operation from the FIFO circuit is initiated byasserting the RD signal to the Read Pointer circuit 96. The Read PointerDecoder circuit 97 then determines the memory cell location within array81 to be read out. The Read Pointer circuit 96 includes a counter thatincrements the memory address location within the array 81 for each readoperation performed. The Read Pointer Decoder circuit 97 determines thememory cell location to read from within the array 81 and provides theproper write voltage biases to memory cell 1, 2, 3, 4, 5, and/or 6terminals as described above.

Full Flag circuit 98 provides the flag signals necessary to indicate theexternal controlling entity when the FIFO memory is full or nearing fullbased on the pace of read and write counter increments. When the FIFObuffer is full, the Full Flag circuit 98 also stops further writeoperations to the memory array 81 to avoid buffer overflow. Empty Flagcircuit 99 provides the flag signals necessary to indicate the externalcontrolling entity when the FIFO memory is empty or nearing empty basedon the pace of read and write counter increments. When the FIFO bufferis empty, the Empty Flag circuit 99 also stops further read operationsto the memory array 81 to avoid invalid data read. In another embodimentof the FIFO circuit above, port #1 of array 81 may be used for readoperation and port #2 of array 81 may be used for write operation.

As discussed in more detail herein, the specific biasing conditions, orvoltages, that are presented herein for the various embodiments ofmemory cells 9 and/or arrays 81 of memory cells 9 are illustrative,non-exclusive examples and their magnitudes may vary based upon avariety of factors. Thus, other biasing conditions are also within thescope of the present disclosure.

Memory cells 9, arrays 81, and/or memory devices 10 according to thepresent disclosure may be utilized for any suitable purpose and/or mayform a portion of any suitable electronic device. These electronicdevices may include additional hardware, illustrative, non-exclusiveexamples of which include one or more microprocessors, logic circuits,user interfaces, displays, input devices, output devices, storagedevices, and/or power supply devices. Illustrative, non-exclusiveexamples of electronic devices according to the present disclosureinclude any suitable printed circuit board, computer, personal computer,laptop computer, and/or cellular telephone.

As used herein, the term “configured” means that the element, component,and/or subject matter is designed and/or intended to perform a givenfunction. This, the term “configured” should not be construed to meanthat a given element, component, or other subject matter is simply“capable of” performing a given function but that the element,component, or other subject matter is specifically selected, created,implemented, utilized, programmed and/or designed for the purpose ofperforming the function.

Illustrative, non-exclusive examples of systems and methods according tothe present disclosure are presented in the following enumeratedparagraphs.

A1. A semiconductor memory cell comprising: a plurality of gates; and acommon body region that is configured to store a charge that isindicative of a memory state of the semiconductor memory cell.

A2. The semiconductor memory cell of paragraph A1, the common bodyregion comprises a first conductivity type, and further wherein thesemiconductor memory cell includes a plurality of conductive regions ofa second conductivity type.

B1. A semiconductor memory cell comprising: a plurality of transistors,wherein each of the plurality of transistors includes a common bodyregion that is configured to store a charge that is indicative of amemory state of said semiconductor memory cell.

B2. The semiconductor memory cell of paragraph B1, wherein common bodyregion is shared among the plurality of transistors.

B3. The semiconductor memory cell of any of paragraphs B1-B2, wherein atleast two of the plurality of transistors is electrically connected inseries.

B4. The semiconductor memory cell of any of paragraphs B1-B3, whereinthe plurality of transistors comprises a plurality of field effecttransistors, and optionally wherein the plurality of transistorsincludes a plurality of metal oxide semiconductor field effecttransistors.

B5. The semiconductor memory cell of any of paragraphs B1-B4, whereinthe plurality of transistors includes a plurality of bipolar devices.

B6. The semiconductor memory cell of any of paragraphs B1-B5, whereinthe plurality of transistors comprises a plurality of gates.

B7. The semiconductor memory cell of any of paragraphs B1-B6, whereinsaid common body region comprises a first conductivity type, and thitherwherein the semiconductor memory cell includes a plurality of conductiveregions of a second conductivity type.

B8. The semiconductor memory cell of paragraph B7, wherein at least oneof the plurality of conductive regions of the second conductivity typeis shared between at least two, and optionally between two, of theplurality of transistors.

C1. A semiconductor memory cell comprising: a common body region; and aplurality of bipolar devices electrically connected in series, whereinthe common body region is shared among the plurality of bipolar devicesand configured to store a charge that is indicative of a memory state ofthe semiconductor memory cell.

C2. The semiconductor memory cell of paragraph C1, wherein thesemiconductor memory cell further includes a plurality of gates.

C3. The semiconductor memory cell of any of paragraphs C1-C2, whereinthe common body region includes a common body region of a firstconductivity type, and thither wherein the semiconductor memory cellincludes a plurality of conductive regions of a second conductivitytype.

D1. The semiconductor memory cell of any of paragraphs A1-C3, whereinthe semiconductor memory cell further includes a plurality of ports.

E1. A semiconductor memory cell comprising: a plurality of ports; acommon body region of a first conductivity type that is configured tostore a charge that is indicative of a memory state of the semiconductormemory cell; and a plurality of conductive regions of a secondconductivity type.

E2. The semiconductor memory cell of paragraph E1, wherein thesemiconductor memory cell further includes a plurality of gates.

F1. The semiconductor memory cell of any of paragraphs A1-A2, B6-B8,C2-C3, or E2.

F2. The semiconductor memory cell of paragraph F1, wherein each of theplurality of gates is capacitively coupled to the common body region.

F3. The semiconductor memory cell of any of paragraphs F1-F2, whereinthe each of the plurality of gates is electrically insulated from thecommon body region by a dielectric material.

F4. The semiconductor memory cell of paragraph F3, wherein thedielectric material includes at least one of an electrically insulatingmaterial, silicon oxide, a high-K dielectric material, tantalumperoxide, titanium oxide, zirconium oxide, hafnium oxide, and aluminumoxide.

F5. The semiconductor memory cell of any of paragraphs F1-F4, whereineach of the plurality of gates is configured to provide at least one,and optionally both, of read access from and write access to thesemiconductor memory cell.

F6. The semiconductor memory cell of any of paragraphs F1-F5, whereineach of the plurality of gates is configured to provide at least one,and optionally both, of read access from and write access to thesemiconductor memory cell independent of the other of the plurality ofgates.

F7. The semiconductor memory cell of any of paragraphs F1-F6, whereinall of the plurality of gates are configured to provide read access fromthe semiconductor memory cell simultaneously.

F8. The semiconductor memory cell of any of paragraphs A2, B8-B9, C3, orE1-E2.

F9. The semiconductor memory cell of paragraph F8, wherein the pluralityof regions of the second conductivity type are electrically coupled tothe common body region.

F10. The semiconductor memory cell of any of paragraphs A2, B8-B9, C3,or E2.

F11. The semiconductor memory cell of paragraph F10, wherein theplurality of gates is spaced apart on a surface of the semiconductormemory cell, wherein the plurality of regions of the second conductivitytype are exposed at the surface of the semiconductor memory cell, andfurther wherein one of the plurality of regions of the secondconductivity type separates each of the plurality of gates from theother of the plurality of gates.

F12. The semiconductor memory cell of any of paragraphs F10-F11, whereinthe semiconductor memory cell includes an even number of gates, andfurther wherein a number of regions of the second conductivity type isone more than the number of gates.

F13. The semiconductor memory cell of any of paragraphs A1-F12, whereinthe semiconductor memory cell includes a fin structure, and optionallywherein the fin structure extends from a substrate.

F14. The semiconductor memory cell of paragraph F13 when dependent fromany of paragraphs F1-F7, wherein the plurality of gates extends from thesubstrate.

F15. The semiconductor memory cell of paragraph F14, wherein the finstructure includes a plurality of sides, and further wherein each of theplurality of gates is present on at least two, and optionally three, ofthe plurality of sides.

F16. The semiconductor memory cell of any of paragraphs F14-F15, whereinthe fin structure includes a longitudinal axis, and further wherein theplurality of gates is spaced apart along the longitudinal axis of thefin structure.

F17. The semiconductor memory cell of any of paragraphs F1-F16, whereinthe plurality of gates is coplanar, and optionally wherein across-section of the semiconductor memory cell passes through the commonbody region and each of the plurality of gates.

G1. A semiconductor memory cell comprising: a plurality of ports; afloating body transistor, wherein the floating body transistor includesa floating body region that is configured to store a charge that isindicative of a memory state of the semiconductor memory cell; and aplurality of access transistors, wherein each of the plurality of accesstransistors corresponds to a respective one of the plurality of ports.

G2. The semiconductor memory cell of paragraph G1, wherein a number ofthe plurality of access transistors is equal to a number of theplurality of ports.

G3. The semiconductor memory cell of any of paragraphs G1-G2, whereinthe plurality of access transistors and the floating body transistor areelectrically connected in series.

G4. The semiconductor memory cell of any of paragraphs G1-G3, whereinthe floating body transistor is configured to receive an electric signalfrom a first access transistor of the plurality of access transistorsand to provide the electric signal to a second access transistor of theplurality of access transistors.

G5. The semiconductor memory cell of any of paragraphs G1-G4, whereinthe floating body transistor electrically separates a first accesstransistor of the plurality of access transistors from a second accesstransistor of the plurality of access transistors.

G6. The semiconductor memory cell of any of paragraphs G1-G5, whereinthe semiconductor memory cell further includes a gate.

G7. The semiconductor memory cell of paragraph G6, wherein the gate iscapacitively coupled to the floating body region.

G8. The semiconductor memory cell of any of paragraphs G6-G7, whereinthe gate is electrically insulated from the floating body region by adielectric material.

G9. The semiconductor memory cell of paragraph G8, wherein thedielectric material includes at least one of an electrically insulatingmaterial, silicon oxide, a high-K dielectric material, tantalumperoxide, titanium oxide, zirconium oxide, hafnium oxide, and aluminumoxide.

G10. The semiconductor memory cell of any of paragraphs G1-G9, whereinthe floating body region includes a floating body region of a firstconductivity type, and further wherein the semiconductor memory cellincludes a plurality of conductive regions of a second conductivitytype.

G11. The semiconductor memory cell of any of paragraphs G1-G10, whereinthe semiconductor memory cell includes a fin structure, and optionallywherein the fin structure extends from a substrate.

G12. The semiconductor memory cell of any of paragraphs G1-G11, whereinthe gate extends from the substrate.

G13. The semiconductor memory cell of paragraph G12, wherein the finstructure includes a plurality of sides, and further wherein the gate ispresent on at least two, and optionally three, of the plurality ofsides.

H1. The semiconductor memory cell of any of paragraphs A1-G13, whereinthe common body region is electrically floating, and optionally whereinthe common body region is a floating body region.

H2. The semiconductor memory cell of any of paragraphs A1-H1, whereinthe semiconductor memory cell is formed on a/the substrate.

H3. The semiconductor memory cell of paragraph H2, wherein the substrateincludes at least one of a bulk silicon substrate and a silicon oninsulator substrate.

H4. The semiconductor memory cell of any of paragraphs H2-H3, whereinthe substrate includes at least one of a substrate of a/the firstconductivity type and a substrate of a/the second conductivity type.

H5. The semiconductor memory cell of any of paragraphs H2-H4, whereinthe common body region is configured to retain a charge, wherein thesubstrate includes a substrate terminal configured to receive asubstrate bias voltage, and further wherein the substrate terminal isconfigured to at least one of inject a charge into and extract thecharge out of the common body region to maintain said memory state ofthe semiconductor memory cell.

H6. The semiconductor memory cell of any of paragraphs A1-H5, whereinthe semiconductor memory cell further includes a buried layer region.

H7. The semiconductor memory cell of paragraph H6 when dependent fromany of paragraphs H2-H5, wherein the buried layer region is locatedbetween the common body region and the substrate.

H8. The semiconductor memory cell of any of paragraphs H6-H7 whendependent from any of paragraphs H2-H5, wherein the buried layer regionseparates the common body region from the substrate.

H9. The semiconductor memory cell of any of paragraphs H6-H8 whendependent from any of paragraphs H2-H5, wherein the buried layer regionincludes a dielectric layer, and optionally wherein the buried layerregion is configured to electrically isolate the common body region fromthe substrate.

H10. The semiconductor memory cell of any of paragraphs A6-H9, whereinthe buried layer region includes a conductive buried layer.

H11. The semiconductor memory cell of paragraph H10 when dependent fromany of paragraphs H2-H9, wherein the buried layer region includes aconductive buried layer region of the second conductivity type, andfurther wherein the substrate includes a substrate of the firstconductivity type.

H12. The semiconductor memory cell of paragraph H11, wherein the buriedlayer region, the substrate, and the common body region form a bipolardevice.

H13. The semiconductor memory cell of any of paragraphs H11-H12 whendependent from any of paragraphs H2-H5, wherein the buried layer regionand the substrate form a diode.

H14. The semiconductor memory cell of any of paragraphs H11-H13, whereinthe buried layer region and the common body region form a diode.

H15. The semiconductor memory cell of any of paragraphs H11-H14, whereinthe common body region is configured to retain a charge, wherein theconductive buried layer region includes a conductive buried layer regionterminal configured to receive a buried layer bias voltage, and furtherwherein the conductive buried layer region terminal is configured to atleast one of inject a charge into and extract the charge out of saidcommon body region to maintain said memory state of the semiconductormemory cell.

H16. The semiconductor memory cell of any of paragraphs A1-H15, whereinthe first conductivity type is one of p-type and n-type, and furtherwherein the second conductivity type is the other of p-type and n-type.

H17. The semiconductor memory cell of any of paragraphs A1-H16, whereinthe semiconductor memory cell includes a/the fin structure, andoptionally wherein the fin structure extends from a/the substrate.

H18. The semiconductor memory cell of paragraph H17, wherein the finstructure includes the common body region.

H19. The semiconductor memory cell of any of paragraphs H17-H18, whereinthe fin structure includes a/the plurality of conductive regions.

H20. The semiconductor memory cell of any of paragraphs H17-H19, whereinthe fin structure is formed on a/the subs hate.

H21. The semiconductor memory cell of paragraph H20, wherein the finstructure includes an elongate fin structure that includes a pluralityof surfaces, and thither wherein a selected one of the plurality ofsurfaces is defined by the substrate.

H22. The semiconductor memory cell of any of paragraphs A1-H21, whereina/the plurality of conductive regions interfaces with the common bodyregion.

H23. The semiconductor memory cell of any of paragraphs A1-H22, whereina/the plurality of conductive regions is in electrical communicationwith the common body region, and optionally wherein the plurality ofconductive regions is in direct electrical communication with the commonbody region.

H24. The semiconductor memory cell of any of paragraphs A1-H23, whereina/the plurality of conductive regions forms a plurality of P-N diodeswith the common body region.

H25. The semiconductor memory cell of any of paragraphs A1-H24, whereineach of a/the plurality of conductive regions is spaced apart from theother of the plurality of conductive regions.

H26. The semiconductor memory cell of paragraph H25, wherein at least aportion of the common body region separates each of the plurality ofconductive regions from the other of the plurality of conductiveregions.

H27. The semiconductor memory cell of any of paragraphs H22-H26, whereineach of the plurality of conductive regions is not in direct electricalcommunication with the other of the plurality of conductive regions.

H28. The semiconductor memory cell of any of paragraphs H22-H27, whereinat least a first conductive region of the plurality of conductiveregions is exposed at a/the surface of a/the substrate.

H29. The semiconductor memory cell of paragraph H28, wherein the buriedlayer region, the common body region, and the at least a firstconductive region of the plurality of conductive regions that is exposedat the surface of the substrate form a bipolar device.

H30. The semiconductor memory cell of any of paragraphs H28-H29, whereinthe substrate, the buried layer region, the common body region, and theat least a first conductive region of the plurality of conductiveregions that is exposed at the surface of the substrate form a siliconcontrolled rectifier device.

H31. The semiconductor memory cell of any of paragraphs H22-H27, whereinat least a first conductive region of the plurality of conductiveregions is beneath a/the surface of a/the substrate.

H32. The semiconductor memory cell of any of paragraphs A1-H31, whereina/the plurality of conductive regions is coplanar, and optionallywherein a cross-section of the semiconductor memory cell passes throughthe common body region and each of the plurality of conductive regions.

I1. A multi-port semiconductor memory cell comprising: the semiconductormemory cell of any of paragraphs A1-H32.

I2. The multi-port semiconductor memory cell of paragraph I1, whereinthe multi-port semiconductor memory cell includes a number of ports,wherein the multi-port semiconductor memory cell includes a number ofgates, and thither wherein the number of ports is equal to the number ofgates.

I3. The multi-port semiconductor memory cell of paragraph I2, whereinthe multi-port semiconductor memory cell includes an even number ofgates and an even number of ports.

I4. The multi-port semiconductor memory cell of any of paragraphs I1-I3,wherein the multi-port semiconductor memory cell includes a/theplurality of conductive regions of a/the second conductivity type, andfurther wherein a number of conductive regions of the secondconductivity type is one more than a number of ports.

I5. The multi-port semiconductor memory cell of any of paragraphs I1-I4,wherein the multi-port semiconductor memory cell includes a/theplurality of ports, and further wherein the plurality of ports iscoplanar, and optionally wherein a cross-section of the multi-portsemiconductor memory cell passes through the common body region and eachof the plurality of ports

J1. A memory device comprising: a plurality of memory cells, wherein theplurality of memory cells includes the semiconductor memory cell of anyof paragraphs A1-I5; a write circuit that is configured to write adesired memory state to the plurality of memory cells; a read circuitthat is configured to determine a current memory state of the pluralityof memory cells; and an input output interface that is configured toreceive the desired memory state from an external device and to providethe current memory state to the external device.

J2. An electronic device comprising: the memory device of paragraph J1;and a logic circuit.

J3. The electronic device of paragraph J2, wherein the logic circuitforms a portion of a microprocessor.

J4. The electronic device of any of paragraphs J2-J3, wherein theelectronic device further includes at least one of a user interface, adisplay, an input device, an output device, a storage device, and apower supply.

J5. The electronic device of any of paragraphs J2-J4, wherein theelectronic device includes at least one of a printed circuit board, acomputer, a personal computer, a laptop computer, and a cellulartelephone.

INDUSTRIAL APPLICABILITY

The systems and methods disclosed herein are applicable to theelectronics industry.

1. A multi-port semiconductor memory cell comprising: a plurality of gates; a common body region of a first conductivity type configured to store a charge that is indicative of a memory state of said memory cell; and a plurality of conductive regions of a second conductivity type, wherein one of the plurality of conductive regions separates each of the plurality of gates from the other of the plurality of gates.
 2. The multi-port semiconductor memory cell of claim 1, wherein each of the plurality of gates is configured to provide at least one of read access from and write access to the multi-port semiconductor memory cell independent of the other of the plurality of gates.
 3. The multi-port semiconductor memory cell of claim 1, wherein the multi-port semiconductor memory cell includes a total number of ports, a total number of gates, and a total number of conductive regions, wherein the total number of ports is equal to the total number of gates, and further wherein the total number of conductive regions is one more than the total number of gates.
 4. The multi-port semiconductor memory cell of claim 1, wherein the plurality of conductive regions is in electrical communication with the common body region, and further wherein each of the plurality of conductive regions is spaced apart from the other of the plurality of conductive regions.
 5. The multi-port semiconductor memory cell of claim 1, wherein at least a portion of the common body region separates each of the plurality of conductive regions from the other of the plurality of conductive regions.
 6. The multi-port semiconductor memory cell of claim 1, wherein the plurality of conductive regions and the common body region form a plurality of diodes.
 7. The multi-port semiconductor memory cell of claim 1, wherein the multi-port semiconductor memory cell includes a fin structure, and further wherein the fin structure includes the common body region.
 8. The multi-port semiconductor memory cell of claim 7, wherein the fin structure is an elongate fin structure that includes a longitudinal axis, and further wherein the plurality of gates is spaced apart along the longitudinal axis.
 9. The multi-port semiconductor memory cell of 7, wherein the fin structure further includes the plurality of conductive regions.
 10. The multi-port semiconductor memory cell of claim 1, wherein the multi-port semiconductor memory cell is formed on a substrate of the second conductivity type, wherein the substrate includes a substrate terminal configured to receive a substrate bias voltage, wherein the common body region is configured to retain a charge, and further wherein a maximum charge of the common body region increases with an increase in the substrate bias voltage.
 11. The multi-port semiconductor memory cell of claim 1, wherein the multi-port semiconductor memory cell is formed on a substrate, wherein the multi-port semiconductor memory cell further includes a buried layer region, and further wherein the buried layer region separates the common body region from the substrate.
 12. The multi-port semiconductor memory cell of claim 11, wherein the buried layer region includes an insulator layer that is configured to electrically isolate the common body region from the substrate.
 13. The multi-port semiconductor memory cell of claim 11, wherein the buried layer region includes a conductive buried layer of the second conductivity type, and further wherein the substrate has the first conductivity type.
 14. The multi-port semiconductor memory cell of claim 13, wherein the conductive buried layer, the common body region, and at least one of said conductive regions of a second conductivity type form a bipolar device.
 15. The multi-port semiconductor memory cell of claim 13, wherein the common body region is configured to retain a charge, wherein the conductive buried layer includes a conductive buried layer terminal that is configured to receive a buried layer bias voltage, and further wherein the buried layer terminal is configured to at least one of inject a charge into and extract the charge out of the common body region to maintain said memory state of the semiconductor memory cell.
 16. (canceled)
 17. A multi-port semiconductor memory cell comprising: a plurality of ports; a floating body transistor, wherein the floating body transistor includes a floating body region configured to store a charge that is indicative of the state of said memory cell; and a plurality of access transistors, wherein each of the plurality of access transistors corresponds to a respective one of the plurality of ports.
 18. The multi-port semiconductor memory cell of claim 17, wherein the floating body transistor is configured to receive an electric signal from a first access transistor of the plurality of access transistors and to provide the electric signal to a second access transistor of the plurality of access transistors.
 19. A semiconductor memory cell comprising: a plurality of transistors, wherein each of the plurality of transistors comprising: a common body region configured to store a charge that is indicative of the state of said memory cell; and a plurality of gates, wherein said common body region is shared among the plurality of transistors, and further wherein said memory cell comprises a terminal configured to at least one of inject a charge into and extract the charge out of the common body region to maintain said memory state of the semiconductor memory cell. 